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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" [
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<!ENTITY % local.common.attrib "xmlns:xi CDATA #FIXED 'http://www.w3.org/2003/XInclude'">
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<!ENTITY version SYSTEM "version.xml">
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<refentry id="gobject-Signals">
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<refentrytitle role="top_of_page" id="gobject-Signals.top_of_page">Signals</refentrytitle>
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<manvolnum>3</manvolnum>
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<refmiscinfo>GOBJECT Library</refmiscinfo>
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<refname>Signals</refname>
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<refpurpose>A means for customization of object behaviour
18
and a general purpose notification mechanism</refpurpose>
21
<refsynopsisdiv id="gobject-Signals.synopsis" role="synopsis">
22
<title role="synopsis.title">Synopsis</title>
26
#include <glib-object.h>
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<link linkend="GSignalInvocationHint">GSignalInvocationHint</link>;
29
<link linkend="gboolean">gboolean</link> (<link linkend="GSignalAccumulator">*GSignalAccumulator</link>) (<link linkend="GSignalInvocationHint">GSignalInvocationHint</link> *ihint,
30
<link linkend="GValue">GValue</link> *return_accu,
31
const <link linkend="GValue">GValue</link> *handler_return,
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<link linkend="gpointer">gpointer</link> data);
33
typedef <link linkend="GSignalCMarshaller">GSignalCMarshaller</link>;
34
<link linkend="gboolean">gboolean</link> (<link linkend="GSignalEmissionHook">*GSignalEmissionHook</link>) (<link linkend="GSignalInvocationHint">GSignalInvocationHint</link> *ihint,
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<link linkend="guint">guint</link> n_param_values,
36
const <link linkend="GValue">GValue</link> *param_values,
37
<link linkend="gpointer">gpointer</link> data);
38
enum <link linkend="GSignalFlags">GSignalFlags</link>;
39
enum <link linkend="GSignalMatchType">GSignalMatchType</link>;
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<link linkend="GSignalQuery">GSignalQuery</link>;
41
#define <link linkend="G-SIGNAL-TYPE-STATIC-SCOPE--CAPS">G_SIGNAL_TYPE_STATIC_SCOPE</link>
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#define <link linkend="G-SIGNAL-MATCH-MASK--CAPS">G_SIGNAL_MATCH_MASK</link>
43
#define <link linkend="G-SIGNAL-FLAGS-MASK--CAPS">G_SIGNAL_FLAGS_MASK</link>
44
<link linkend="guint">guint</link> <link linkend="g-signal-new">g_signal_new</link> (const <link linkend="gchar">gchar</link> *signal_name,
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<link linkend="GType">GType</link> itype,
46
<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
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<link linkend="guint">guint</link> class_offset,
48
<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
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<link linkend="gpointer">gpointer</link> accu_data,
50
<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
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<link linkend="GType">GType</link> return_type,
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<link linkend="guint">guint</link> n_params,
54
<link linkend="guint">guint</link> <link linkend="g-signal-newv">g_signal_newv</link> (const <link linkend="gchar">gchar</link> *signal_name,
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<link linkend="GType">GType</link> itype,
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<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
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<link linkend="GClosure">GClosure</link> *class_closure,
58
<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
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<link linkend="gpointer">gpointer</link> accu_data,
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<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
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<link linkend="GType">GType</link> return_type,
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<link linkend="guint">guint</link> n_params,
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<link linkend="GType">GType</link> *param_types);
64
<link linkend="guint">guint</link> <link linkend="g-signal-new-valist">g_signal_new_valist</link> (const <link linkend="gchar">gchar</link> *signal_name,
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<link linkend="GType">GType</link> itype,
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<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
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<link linkend="GClosure">GClosure</link> *class_closure,
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<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
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<link linkend="gpointer">gpointer</link> accu_data,
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<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
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<link linkend="GType">GType</link> return_type,
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<link linkend="guint">guint</link> n_params,
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<link linkend="va-list">va_list</link> args);
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<link linkend="void">void</link> <link linkend="g-signal-query">g_signal_query</link> (<link linkend="guint">guint</link> signal_id,
75
<link linkend="GSignalQuery">GSignalQuery</link> *query);
76
<link linkend="guint">guint</link> <link linkend="g-signal-lookup">g_signal_lookup</link> (const <link linkend="gchar">gchar</link> *name,
77
<link linkend="GType">GType</link> itype);
78
const <link linkend="gchar">gchar</link>* <link linkend="g-signal-name">g_signal_name</link> (<link linkend="guint">guint</link> signal_id);
79
<link linkend="guint">guint</link>* <link linkend="g-signal-list-ids">g_signal_list_ids</link> (<link linkend="GType">GType</link> itype,
80
<link linkend="guint">guint</link> *n_ids);
81
<link linkend="void">void</link> <link linkend="g-signal-emit">g_signal_emit</link> (<link linkend="gpointer">gpointer</link> instance,
82
<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="void">void</link> <link linkend="g-signal-emit-by-name">g_signal_emit_by_name</link> (<link linkend="gpointer">gpointer</link> instance,
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const <link linkend="gchar">gchar</link> *detailed_signal,
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<link linkend="void">void</link> <link linkend="g-signal-emitv">g_signal_emitv</link> (const <link linkend="GValue">GValue</link> *instance_and_params,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="GValue">GValue</link> *return_value);
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<link linkend="void">void</link> <link linkend="g-signal-emit-valist">g_signal_emit_valist</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="va-list">va_list</link> var_args);
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#define <link linkend="g-signal-connect">g_signal_connect</link> (instance, detailed_signal, c_handler, data)
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#define <link linkend="g-signal-connect-after">g_signal_connect_after</link> (instance, detailed_signal, c_handler, data)
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#define <link linkend="g-signal-connect-swapped">g_signal_connect_swapped</link> (instance, detailed_signal, c_handler, data)
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<link linkend="gulong">gulong</link> <link linkend="g-signal-connect-object">g_signal_connect_object</link> (<link linkend="gpointer">gpointer</link> instance,
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const <link linkend="gchar">gchar</link> *detailed_signal,
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<link linkend="GCallback">GCallback</link> c_handler,
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<link linkend="gpointer">gpointer</link> gobject,
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<link linkend="GConnectFlags">GConnectFlags</link> connect_flags);
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enum <link linkend="GConnectFlags">GConnectFlags</link>;
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<link linkend="gulong">gulong</link> <link linkend="g-signal-connect-data">g_signal_connect_data</link> (<link linkend="gpointer">gpointer</link> instance,
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const <link linkend="gchar">gchar</link> *detailed_signal,
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<link linkend="GCallback">GCallback</link> c_handler,
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<link linkend="gpointer">gpointer</link> data,
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<link linkend="GClosureNotify">GClosureNotify</link> destroy_data,
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<link linkend="GConnectFlags">GConnectFlags</link> connect_flags);
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<link linkend="gulong">gulong</link> <link linkend="g-signal-connect-closure">g_signal_connect_closure</link> (<link linkend="gpointer">gpointer</link> instance,
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const <link linkend="gchar">gchar</link> *detailed_signal,
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<link linkend="GClosure">GClosure</link> *closure,
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<link linkend="gboolean">gboolean</link> after);
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<link linkend="gulong">gulong</link> <link linkend="g-signal-connect-closure-by-id">g_signal_connect_closure_by_id</link> (<link linkend="gpointer">gpointer</link> instance,
116
<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="GClosure">GClosure</link> *closure,
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<link linkend="gboolean">gboolean</link> after);
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<link linkend="void">void</link> <link linkend="g-signal-handler-block">g_signal_handler_block</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="gulong">gulong</link> handler_id);
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<link linkend="void">void</link> <link linkend="g-signal-handler-unblock">g_signal_handler_unblock</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="gulong">gulong</link> handler_id);
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<link linkend="void">void</link> <link linkend="g-signal-handler-disconnect">g_signal_handler_disconnect</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="gulong">gulong</link> handler_id);
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<link linkend="gulong">gulong</link> <link linkend="g-signal-handler-find">g_signal_handler_find</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="GClosure">GClosure</link> *closure,
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<link linkend="gpointer">gpointer</link> func,
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<link linkend="gpointer">gpointer</link> data);
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<link linkend="guint">guint</link> <link linkend="g-signal-handlers-block-matched">g_signal_handlers_block_matched</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="GClosure">GClosure</link> *closure,
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<link linkend="gpointer">gpointer</link> func,
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<link linkend="gpointer">gpointer</link> data);
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<link linkend="guint">guint</link> <link linkend="g-signal-handlers-unblock-matched">g_signal_handlers_unblock_matched</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="GClosure">GClosure</link> *closure,
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<link linkend="gpointer">gpointer</link> func,
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<link linkend="gpointer">gpointer</link> data);
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<link linkend="guint">guint</link> <link linkend="g-signal-handlers-disconnect-matched">g_signal_handlers_disconnect_matched</link>
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(<link linkend="gpointer">gpointer</link> instance,
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<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="GClosure">GClosure</link> *closure,
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<link linkend="gpointer">gpointer</link> func,
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<link linkend="gpointer">gpointer</link> data);
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<link linkend="gboolean">gboolean</link> <link linkend="g-signal-handler-is-connected">g_signal_handler_is_connected</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="gulong">gulong</link> handler_id);
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#define <link linkend="g-signal-handlers-block-by-func">g_signal_handlers_block_by_func</link> (instance, func, data)
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#define <link linkend="g-signal-handlers-unblock-by-func">g_signal_handlers_unblock_by_func</link> (instance, func, data)
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#define <link linkend="g-signal-handlers-disconnect-by-func">g_signal_handlers_disconnect_by_func</link>(instance, func, data)
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<link linkend="gboolean">gboolean</link> <link linkend="g-signal-has-handler-pending">g_signal_has_handler_pending</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail,
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<link linkend="gboolean">gboolean</link> may_be_blocked);
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<link linkend="void">void</link> <link linkend="g-signal-stop-emission">g_signal_stop_emission</link> (<link linkend="gpointer">gpointer</link> instance,
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<link linkend="guint">guint</link> signal_id,
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<link linkend="GQuark">GQuark</link> detail);
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<link linkend="void">void</link> <link linkend="g-signal-stop-emission-by-name">g_signal_stop_emission_by_name</link> (<link linkend="gpointer">gpointer</link> instance,
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const <link linkend="gchar">gchar</link> *detailed_signal);
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<link linkend="void">void</link> <link linkend="g-signal-override-class-closure">g_signal_override_class_closure</link> (<link linkend="guint">guint</link> signal_id,
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<link linkend="GType">GType</link> instance_type,
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<link linkend="GClosure">GClosure</link> *class_closure);
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<link linkend="void">void</link> <link linkend="g-signal-chain-from-overridden">g_signal_chain_from_overridden</link> (const <link linkend="GValue">GValue</link> *instance_and_params,
173
<link linkend="GValue">GValue</link> *return_value);
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<link linkend="guint">guint</link> <link linkend="g-signal-new-class-handler">g_signal_new_class_handler</link> (const <link linkend="gchar">gchar</link> *signal_name,
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<link linkend="GType">GType</link> itype,
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<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
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<link linkend="GCallback">GCallback</link> class_handler,
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<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
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<link linkend="gpointer">gpointer</link> accu_data,
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<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
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<link linkend="GType">GType</link> return_type,
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<link linkend="guint">guint</link> n_params,
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<link linkend="void">void</link> <link linkend="g-signal-override-class-handler">g_signal_override_class_handler</link> (const <link linkend="gchar">gchar</link> *signal_name,
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<link linkend="GType">GType</link> instance_type,
186
<link linkend="GCallback">GCallback</link> class_handler);
187
<link linkend="void">void</link> <link linkend="g-signal-chain-from-overridden-handler">g_signal_chain_from_overridden_handler</link>
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(<link linkend="gpointer">gpointer</link> instance,
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<link linkend="gulong">gulong</link> <link linkend="g-signal-add-emission-hook">g_signal_add_emission_hook</link> (<link linkend="guint">guint</link> signal_id,
191
<link linkend="GQuark">GQuark</link> detail,
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<link linkend="GSignalEmissionHook">GSignalEmissionHook</link> hook_func,
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<link linkend="gpointer">gpointer</link> hook_data,
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<link linkend="GDestroyNotify">GDestroyNotify</link> data_destroy);
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<link linkend="void">void</link> <link linkend="g-signal-remove-emission-hook">g_signal_remove_emission_hook</link> (<link linkend="guint">guint</link> signal_id,
196
<link linkend="gulong">gulong</link> hook_id);
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<link linkend="gboolean">gboolean</link> <link linkend="g-signal-parse-name">g_signal_parse_name</link> (const <link linkend="gchar">gchar</link> *detailed_signal,
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<link linkend="GType">GType</link> itype,
199
<link linkend="guint">guint</link> *signal_id_p,
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<link linkend="GQuark">GQuark</link> *detail_p,
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<link linkend="gboolean">gboolean</link> force_detail_quark);
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<link linkend="GSignalInvocationHint">GSignalInvocationHint</link>* <link linkend="g-signal-get-invocation-hint">g_signal_get_invocation_hint</link> (<link linkend="gpointer">gpointer</link> instance);
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<link linkend="GClosure">GClosure</link>* <link linkend="g-signal-type-cclosure-new">g_signal_type_cclosure_new</link> (<link linkend="GType">GType</link> itype,
204
<link linkend="guint">guint</link> struct_offset);
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<link linkend="gboolean">gboolean</link> <link linkend="g-signal-accumulator-true-handled">g_signal_accumulator_true_handled</link> (<link linkend="GSignalInvocationHint">GSignalInvocationHint</link> *ihint,
206
<link linkend="GValue">GValue</link> *return_accu,
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const <link linkend="GValue">GValue</link> *handler_return,
208
<link linkend="gpointer">gpointer</link> dummy);
220
<refsect1 id="gobject-Signals.description" role="desc">
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<title role="desc.title">Description</title>
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The basic concept of the signal system is that of the
224
<emphasis>emission</emphasis> of a signal. Signals are introduced
225
per-type and are identified through strings. Signals introduced
226
for a parent type are available in derived types as well, so
227
basically they are a per-type facility that is inherited. A signal
228
emission mainly involves invocation of a certain set of callbacks
229
in precisely defined manner. There are two main categories of such
230
callbacks, per-object
231
<footnote><para>Although signals can deal with any kind of instantiatable
232
type, i'm referring to those types as "object types" in the following,
233
simply because that is the context most users will encounter signals in.
235
ones and user provided ones.
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The per-object callbacks are most often referred to as "object method
237
handler" or "default (signal) handler", while user provided callbacks are
238
usually just called "signal handler".
239
The object method handler is provided at signal creation time (this most
240
frequently happens at the end of an object class' creation), while user
241
provided handlers are frequently connected and disconnected to/from a certain
242
signal on certain object instances.
245
A signal emission consists of five stages, unless prematurely stopped:
247
<varlistentry><term></term><listitem><para>
248
1 - Invocation of the object method handler for <link linkend="G-SIGNAL-RUN-FIRST--CAPS"><literal>G_SIGNAL_RUN_FIRST</literal></link> signals
249
</para></listitem></varlistentry>
250
<varlistentry><term></term><listitem><para>
251
2 - Invocation of normal user-provided signal handlers (<emphasis>after</emphasis> flag <link linkend="FALSE--CAPS"><literal>FALSE</literal></link>)
252
</para></listitem></varlistentry>
253
<varlistentry><term></term><listitem><para>
254
3 - Invocation of the object method handler for <link linkend="G-SIGNAL-RUN-LAST--CAPS"><literal>G_SIGNAL_RUN_LAST</literal></link> signals
255
</para></listitem></varlistentry>
256
<varlistentry><term></term><listitem><para>
257
4 - Invocation of user provided signal handlers, connected with an <emphasis>after</emphasis> flag of <link linkend="TRUE--CAPS"><literal>TRUE</literal></link>
258
</para></listitem></varlistentry>
259
<varlistentry><term></term><listitem><para>
260
5 - Invocation of the object method handler for <link linkend="G-SIGNAL-RUN-CLEANUP--CAPS"><literal>G_SIGNAL_RUN_CLEANUP</literal></link> signals
261
</para></listitem></varlistentry>
263
The user-provided signal handlers are called in the order they were
265
All handlers may prematurely stop a signal emission, and any number of
266
handlers may be connected, disconnected, blocked or unblocked during
268
There are certain criteria for skipping user handlers in stages 2 and 4
269
of a signal emission.
270
First, user handlers may be <emphasis>blocked</emphasis>, blocked handlers are omitted
271
during callback invocation, to return from the "blocked" state, a
272
handler has to get unblocked exactly the same amount of times
273
it has been blocked before.
274
Second, upon emission of a <link linkend="G-SIGNAL-DETAILED--CAPS"><literal>G_SIGNAL_DETAILED</literal></link> signal, an additional
275
"detail" argument passed in to <link linkend="g-signal-emit"><function>g_signal_emit()</function></link> has to match the detail
276
argument of the signal handler currently subject to invocation.
277
Specification of no detail argument for signal handlers (omission of the
278
detail part of the signal specification upon connection) serves as a
279
wildcard and matches any detail argument passed in to emission.</para>
284
<refsect1 id="gobject-Signals.details" role="details">
285
<title role="details.title">Details</title>
286
<refsect2 id="GSignalInvocationHint" role="struct">
287
<title>GSignalInvocationHint</title>
288
<indexterm zone="GSignalInvocationHint"><primary sortas="SignalInvocationHint">GSignalInvocationHint</primary></indexterm><programlisting>typedef struct {
291
GSignalFlags run_type;
292
} GSignalInvocationHint;
295
The <link linkend="GSignalInvocationHint"><type>GSignalInvocationHint</type></link> structure is used to pass on additional information
296
to callbacks during a signal emission.</para>
298
</para><variablelist role="struct">
300
<term><link linkend="guint">guint</link> <structfield>signal_id</structfield>;</term>
301
<listitem><simpara> The signal id of the signal invoking the callback
302
</simpara></listitem>
305
<term><link linkend="GQuark">GQuark</link> <structfield>detail</structfield>;</term>
306
<listitem><simpara> The detail passed on for this emission
307
</simpara></listitem>
310
<term><link linkend="GSignalFlags">GSignalFlags</link> <structfield>run_type</structfield>;</term>
311
<listitem><simpara> The stage the signal emission is currently in, this
312
field will contain one of <link linkend="G-SIGNAL-RUN-FIRST--CAPS"><literal>G_SIGNAL_RUN_FIRST</literal></link>,
313
<link linkend="G-SIGNAL-RUN-LAST--CAPS"><literal>G_SIGNAL_RUN_LAST</literal></link> or <link linkend="G-SIGNAL-RUN-CLEANUP--CAPS"><literal>G_SIGNAL_RUN_CLEANUP</literal></link>.
314
</simpara></listitem>
316
</variablelist></refsect2>
317
<refsect2 id="GSignalAccumulator" role="function">
318
<title>GSignalAccumulator ()</title>
319
<indexterm zone="GSignalAccumulator"><primary sortas="SignalAccumulator">GSignalAccumulator</primary></indexterm><programlisting><link linkend="gboolean">gboolean</link> (*GSignalAccumulator) (<link linkend="GSignalInvocationHint">GSignalInvocationHint</link> *ihint,
320
<link linkend="GValue">GValue</link> *return_accu,
321
const <link linkend="GValue">GValue</link> *handler_return,
322
<link linkend="gpointer">gpointer</link> data);</programlisting>
324
The signal accumulator is a special callback function that can be used
325
to collect return values of the various callbacks that are called
326
during a signal emission. The signal accumulator is specified at signal
327
creation time, if it is left <link linkend="NULL--CAPS"><literal>NULL</literal></link>, no accumulation of callback return
328
values is performed. The return value of signal emissions is then the
329
value returned by the last callback.</para>
331
</para><variablelist role="params">
332
<varlistentry><term><parameter>ihint</parameter> :</term>
333
<listitem><simpara> Signal invocation hint, see <link linkend="GSignalInvocationHint"><type>GSignalInvocationHint</type></link>.
334
</simpara></listitem></varlistentry>
335
<varlistentry><term><parameter>return_accu</parameter> :</term>
336
<listitem><simpara> Accumulator to collect callback return values in, this
337
is the return value of the current signal emission.
338
</simpara></listitem></varlistentry>
339
<varlistentry><term><parameter>handler_return</parameter> :</term>
340
<listitem><simpara> A <link linkend="GValue"><type>GValue</type></link> holding the return value of the signal handler.
341
</simpara></listitem></varlistentry>
342
<varlistentry><term><parameter>data</parameter> :</term>
343
<listitem><simpara> Callback data that was specified when creating the signal.
344
</simpara></listitem></varlistentry>
345
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> The accumulator function returns whether the signal emission
346
should be aborted. Returning <link linkend="FALSE--CAPS"><literal>FALSE</literal></link> means to abort the
347
current emission and <link linkend="TRUE--CAPS"><literal>TRUE</literal></link> is returned for continuation.
348
</simpara></listitem></varlistentry>
349
</variablelist></refsect2>
350
<refsect2 id="GSignalCMarshaller" role="typedef">
351
<title>GSignalCMarshaller</title>
352
<indexterm zone="GSignalCMarshaller"><primary sortas="SignalCMarshaller">GSignalCMarshaller</primary></indexterm><programlisting>typedef GClosureMarshal GSignalCMarshaller;
355
This is the signature of marshaller functions, required to marshall
356
arrays of parameter values to signal emissions into C language callback
357
invocations. It is merely an alias to <link linkend="GClosureMarshal"><type>GClosureMarshal</type></link> since the <link linkend="GClosure"><type>GClosure</type></link>
358
mechanism takes over responsibility of actual function invocation for the
359
signal system.</para>
362
<refsect2 id="GSignalEmissionHook" role="function">
363
<title>GSignalEmissionHook ()</title>
364
<indexterm zone="GSignalEmissionHook"><primary sortas="SignalEmissionHook">GSignalEmissionHook</primary></indexterm><programlisting><link linkend="gboolean">gboolean</link> (*GSignalEmissionHook) (<link linkend="GSignalInvocationHint">GSignalInvocationHint</link> *ihint,
365
<link linkend="guint">guint</link> n_param_values,
366
const <link linkend="GValue">GValue</link> *param_values,
367
<link linkend="gpointer">gpointer</link> data);</programlisting>
369
A simple function pointer to get invoked when the signal is emitted. This
370
allows you to tie a hook to the signal type, so that it will trap all
371
emissions of that signal, from any object.
374
You may not attach these to signals created with the <link linkend="G-SIGNAL-NO-HOOKS--CAPS"><type>G_SIGNAL_NO_HOOKS</type></link> flag.</para>
376
</para><variablelist role="params">
377
<varlistentry><term><parameter>ihint</parameter> :</term>
378
<listitem><simpara> Signal invocation hint, see <link linkend="GSignalInvocationHint"><type>GSignalInvocationHint</type></link>.
379
</simpara></listitem></varlistentry>
380
<varlistentry><term><parameter>n_param_values</parameter> :</term>
381
<listitem><simpara> the number of parameters to the function, including
382
the instance on which the signal was emitted.
383
</simpara></listitem></varlistentry>
384
<varlistentry><term><parameter>param_values</parameter> :</term>
385
<listitem><simpara> the instance on which the signal was emitted, followed by the
386
parameters of the emission.
387
</simpara></listitem></varlistentry>
388
<varlistentry><term><parameter>data</parameter> :</term>
389
<listitem><simpara> user data associated with the hook.
390
</simpara></listitem></varlistentry>
391
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> whether it wants to stay connected. If it returns <link linkend="FALSE--CAPS"><literal>FALSE</literal></link>, the signal
392
hook is disconnected (and destroyed).
393
</simpara></listitem></varlistentry>
394
</variablelist></refsect2>
395
<refsect2 id="GSignalFlags" role="enum">
396
<title>enum GSignalFlags</title>
397
<indexterm zone="GSignalFlags"><primary sortas="SignalFlags">GSignalFlags</primary></indexterm><programlisting>typedef enum
399
G_SIGNAL_RUN_FIRST = 1 << 0,
400
G_SIGNAL_RUN_LAST = 1 << 1,
401
G_SIGNAL_RUN_CLEANUP = 1 << 2,
402
G_SIGNAL_NO_RECURSE = 1 << 3,
403
G_SIGNAL_DETAILED = 1 << 4,
404
G_SIGNAL_ACTION = 1 << 5,
405
G_SIGNAL_NO_HOOKS = 1 << 6
409
The signal flags are used to specify a signal's behaviour, the overall
410
signal description outlines how especially the RUN flags control the
411
stages of a signal emission.</para>
413
</para><variablelist role="enum">
414
<varlistentry id="G-SIGNAL-RUN-FIRST--CAPS" role="constant">
415
<term><literal>G_SIGNAL_RUN_FIRST</literal></term>
416
<listitem><simpara> Invoke the object method handler in the first emission stage.
417
</simpara></listitem>
419
<varlistentry id="G-SIGNAL-RUN-LAST--CAPS" role="constant">
420
<term><literal>G_SIGNAL_RUN_LAST</literal></term>
421
<listitem><simpara> Invoke the object method handler in the third emission stage.
422
</simpara></listitem>
424
<varlistentry id="G-SIGNAL-RUN-CLEANUP--CAPS" role="constant">
425
<term><literal>G_SIGNAL_RUN_CLEANUP</literal></term>
426
<listitem><simpara> Invoke the object method handler in the last emission stage.
427
</simpara></listitem>
429
<varlistentry id="G-SIGNAL-NO-RECURSE--CAPS" role="constant">
430
<term><literal>G_SIGNAL_NO_RECURSE</literal></term>
431
<listitem><simpara> Signals being emitted for an object while currently being in
432
emission for this very object will not be emitted recursively,
433
but instead cause the first emission to be restarted.
434
</simpara></listitem>
436
<varlistentry id="G-SIGNAL-DETAILED--CAPS" role="constant">
437
<term><literal>G_SIGNAL_DETAILED</literal></term>
438
<listitem><simpara> This signal supports "::detail" appendices to the signal name
439
upon handler connections and emissions.
440
</simpara></listitem>
442
<varlistentry id="G-SIGNAL-ACTION--CAPS" role="constant">
443
<term><literal>G_SIGNAL_ACTION</literal></term>
444
<listitem><simpara> Action signals are signals that may freely be emitted on alive
445
objects from user code via <link linkend="g-signal-emit"><function>g_signal_emit()</function></link> and friends, without
446
the need of being embedded into extra code that performs pre or
447
post emission adjustments on the object. They can also be thought
448
of as object methods which can be called generically by
450
</simpara></listitem>
452
<varlistentry id="G-SIGNAL-NO-HOOKS--CAPS" role="constant">
453
<term><literal>G_SIGNAL_NO_HOOKS</literal></term>
454
<listitem><simpara> No emissions hooks are supported for this signal.
455
</simpara></listitem>
457
</variablelist></refsect2>
458
<refsect2 id="GSignalMatchType" role="enum">
459
<title>enum GSignalMatchType</title>
460
<indexterm zone="GSignalMatchType"><primary sortas="SignalMatchType">GSignalMatchType</primary></indexterm><programlisting>typedef enum
462
G_SIGNAL_MATCH_ID = 1 << 0,
463
G_SIGNAL_MATCH_DETAIL = 1 << 1,
464
G_SIGNAL_MATCH_CLOSURE = 1 << 2,
465
G_SIGNAL_MATCH_FUNC = 1 << 3,
466
G_SIGNAL_MATCH_DATA = 1 << 4,
467
G_SIGNAL_MATCH_UNBLOCKED = 1 << 5
471
The match types specify what <link linkend="g-signal-handlers-block-matched"><function>g_signal_handlers_block_matched()</function></link>,
472
<link linkend="g-signal-handlers-unblock-matched"><function>g_signal_handlers_unblock_matched()</function></link> and <link linkend="g-signal-handlers-disconnect-matched"><function>g_signal_handlers_disconnect_matched()</function></link>
473
match signals by.</para>
475
</para><variablelist role="enum">
476
<varlistentry id="G-SIGNAL-MATCH-ID--CAPS" role="constant">
477
<term><literal>G_SIGNAL_MATCH_ID</literal></term>
478
<listitem><simpara> The signal id must be equal.
479
</simpara></listitem>
481
<varlistentry id="G-SIGNAL-MATCH-DETAIL--CAPS" role="constant">
482
<term><literal>G_SIGNAL_MATCH_DETAIL</literal></term>
483
<listitem><simpara> The signal detail be equal.
484
</simpara></listitem>
486
<varlistentry id="G-SIGNAL-MATCH-CLOSURE--CAPS" role="constant">
487
<term><literal>G_SIGNAL_MATCH_CLOSURE</literal></term>
488
<listitem><simpara> The closure must be the same.
489
</simpara></listitem>
491
<varlistentry id="G-SIGNAL-MATCH-FUNC--CAPS" role="constant">
492
<term><literal>G_SIGNAL_MATCH_FUNC</literal></term>
493
<listitem><simpara> The C closure callback must be the same.
494
</simpara></listitem>
496
<varlistentry id="G-SIGNAL-MATCH-DATA--CAPS" role="constant">
497
<term><literal>G_SIGNAL_MATCH_DATA</literal></term>
498
<listitem><simpara> The closure data must be the same.
499
</simpara></listitem>
501
<varlistentry id="G-SIGNAL-MATCH-UNBLOCKED--CAPS" role="constant">
502
<term><literal>G_SIGNAL_MATCH_UNBLOCKED</literal></term>
503
<listitem><simpara> Only unblocked signals may matched.
504
</simpara></listitem>
506
</variablelist></refsect2>
507
<refsect2 id="GSignalQuery" role="struct">
508
<title>GSignalQuery</title>
509
<indexterm zone="GSignalQuery"><primary sortas="SignalQuery">GSignalQuery</primary></indexterm><programlisting>typedef struct {
511
const gchar *signal_name;
513
GSignalFlags signal_flags;
514
GType return_type; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
516
const GType *param_types; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
520
A structure holding in-depth information for a specific signal. It is
521
filled in by the <link linkend="g-signal-query"><function>g_signal_query()</function></link> function.</para>
523
</para><variablelist role="struct">
525
<term><link linkend="guint">guint</link> <structfield>signal_id</structfield>;</term>
526
<listitem><simpara> The signal id of the signal being queried, or 0 if the
527
signal to be queried was unknown.
528
</simpara></listitem>
531
<term>const <link linkend="gchar">gchar</link> *<structfield>signal_name</structfield>;</term>
532
<listitem><simpara> The signal name.
533
</simpara></listitem>
536
<term><link linkend="GType">GType</link> <structfield>itype</structfield>;</term>
537
<listitem><simpara> The interface/instance type that this signal can be emitted for.
538
</simpara></listitem>
541
<term><link linkend="GSignalFlags">GSignalFlags</link> <structfield>signal_flags</structfield>;</term>
542
<listitem><simpara> The signal flags as passed in to <link linkend="g-signal-new"><function>g_signal_new()</function></link>.
543
</simpara></listitem>
546
<term><link linkend="GType">GType</link> <structfield>return_type</structfield>;</term>
547
<listitem><simpara> The return type for user callbacks.
548
</simpara></listitem>
551
<term><link linkend="guint">guint</link> <structfield>n_params</structfield>;</term>
552
<listitem><simpara> The number of parameters that user callbacks take.
553
</simpara></listitem>
556
<term>const <link linkend="GType">GType</link> *<structfield>param_types</structfield>;</term>
557
<listitem><simpara> The individual parameter types for user callbacks, note that the
558
effective callback signature is:
560
@return_type callback (<link linkend="gpointer">gpointer</link> data1,
561
[<link linkend="param-types">param_types</link> param_names,]
562
<link linkend="gpointer">gpointer</link> data2);
564
</simpara></listitem>
566
</variablelist></refsect2>
567
<refsect2 id="G-SIGNAL-TYPE-STATIC-SCOPE--CAPS" role="macro">
568
<title>G_SIGNAL_TYPE_STATIC_SCOPE</title>
569
<indexterm zone="G-SIGNAL-TYPE-STATIC-SCOPE--CAPS"><primary sortas="SIGNAL_TYPE_STATIC_SCOPE">G_SIGNAL_TYPE_STATIC_SCOPE</primary></indexterm><programlisting>#define G_SIGNAL_TYPE_STATIC_SCOPE (G_TYPE_FLAG_RESERVED_ID_BIT)
572
This macro flags signal argument types for which the signal system may
573
assume that instances thereof remain persistent across all signal emissions
574
they are used in. This is only useful for non ref-counted, value-copy types.
577
To flag a signal argument in this way, add
578
<literal>| G_SIGNAL_TYPE_STATIC_SCOPE</literal> to the corresponding argument
579
of <link linkend="g-signal-new"><function>g_signal_new()</function></link>.
580
<informalexample><programlisting>
581
g_signal_new ("size_request",
582
G_TYPE_FROM_CLASS (gobject_class),
584
G_STRUCT_OFFSET (GtkWidgetClass, size_request),
586
_gtk_marshal_VOID__BOXED,
588
GTK_TYPE_REQUISITION | G_SIGNAL_TYPE_STATIC_SCOPE);
589
</programlisting></informalexample></para>
592
<refsect2 id="G-SIGNAL-MATCH-MASK--CAPS" role="macro">
593
<title>G_SIGNAL_MATCH_MASK</title>
594
<indexterm zone="G-SIGNAL-MATCH-MASK--CAPS"><primary sortas="SIGNAL_MATCH_MASK">G_SIGNAL_MATCH_MASK</primary></indexterm><programlisting>#define G_SIGNAL_MATCH_MASK 0x3f
597
A mask for all <link linkend="GSignalMatchType"><type>GSignalMatchType</type></link> bits.</para>
600
<refsect2 id="G-SIGNAL-FLAGS-MASK--CAPS" role="macro">
601
<title>G_SIGNAL_FLAGS_MASK</title>
602
<indexterm zone="G-SIGNAL-FLAGS-MASK--CAPS"><primary sortas="SIGNAL_FLAGS_MASK">G_SIGNAL_FLAGS_MASK</primary></indexterm><programlisting>#define G_SIGNAL_FLAGS_MASK 0x7f
605
A mask for all <link linkend="GSignalFlags"><type>GSignalFlags</type></link> bits.</para>
608
<refsect2 id="g-signal-new" role="function">
609
<title>g_signal_new ()</title>
610
<indexterm zone="g-signal-new"><primary sortas="signal_new">g_signal_new</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_new (const <link linkend="gchar">gchar</link> *signal_name,
611
<link linkend="GType">GType</link> itype,
612
<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
613
<link linkend="guint">guint</link> class_offset,
614
<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
615
<link linkend="gpointer">gpointer</link> accu_data,
616
<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
617
<link linkend="GType">GType</link> return_type,
618
<link linkend="guint">guint</link> n_params,
619
...);</programlisting>
621
Creates a new signal. (This is usually done in the class initializer.)
624
A signal name consists of segments consisting of ASCII letters and
625
digits, separated by either the '-' or '_' character. The first
626
character of a signal name must be a letter. Names which violate these
627
rules lead to undefined behaviour of the GSignal system.
630
When registering a signal and looking up a signal, either separator can
631
be used, but they cannot be mixed.
634
If 0 is used for <parameter>class_offset</parameter> subclasses cannot override the class handler
635
in their <code>class_init</code> method by doing
636
<code>super_class->signal_handler = my_signal_handler</code>. Instead they
637
will have to use <link linkend="g-signal-override-class-handler"><function>g_signal_override_class_handler()</function></link>.</para>
639
</para><variablelist role="params">
640
<varlistentry><term><parameter>signal_name</parameter> :</term>
641
<listitem><simpara> the name for the signal
642
</simpara></listitem></varlistentry>
643
<varlistentry><term><parameter>itype</parameter> :</term>
644
<listitem><simpara> the type this signal pertains to. It will also pertain to
645
types which are derived from this type.
646
</simpara></listitem></varlistentry>
647
<varlistentry><term><parameter>signal_flags</parameter> :</term>
648
<listitem><simpara> a combination of <link linkend="GSignalFlags"><type>GSignalFlags</type></link> specifying detail of when
649
the default handler is to be invoked. You should at least specify
650
<link linkend="G-SIGNAL-RUN-FIRST--CAPS"><literal>G_SIGNAL_RUN_FIRST</literal></link> or <link linkend="G-SIGNAL-RUN-LAST--CAPS"><literal>G_SIGNAL_RUN_LAST</literal></link>.
651
</simpara></listitem></varlistentry>
652
<varlistentry><term><parameter>class_offset</parameter> :</term>
653
<listitem><simpara> The offset of the function pointer in the class structure
654
for this type. Used to invoke a class method generically. Pass 0 to
655
not associate a class method slot with this signal.
656
</simpara></listitem></varlistentry>
657
<varlistentry><term><parameter>accumulator</parameter> :</term>
658
<listitem><simpara> the accumulator for this signal; may be <link linkend="NULL--CAPS"><literal>NULL</literal></link>.
659
</simpara></listitem></varlistentry>
660
<varlistentry><term><parameter>accu_data</parameter> :</term>
661
<listitem><simpara> user data for the <parameter>accumulator</parameter>.
662
</simpara></listitem></varlistentry>
663
<varlistentry><term><parameter>c_marshaller</parameter> :</term>
664
<listitem><simpara> the function to translate arrays of parameter values to
665
signal emissions into C language callback invocations.
666
</simpara></listitem></varlistentry>
667
<varlistentry><term><parameter>return_type</parameter> :</term>
668
<listitem><simpara> the type of return value, or <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link> for a signal
669
without a return value.
670
</simpara></listitem></varlistentry>
671
<varlistentry><term><parameter>n_params</parameter> :</term>
672
<listitem><simpara> the number of parameter types to follow.
673
</simpara></listitem></varlistentry>
674
<varlistentry><term><parameter>...</parameter> :</term>
675
<listitem><simpara> a list of types, one for each parameter.
676
</simpara></listitem></varlistentry>
677
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the signal id
678
</simpara></listitem></varlistentry>
679
</variablelist></refsect2>
680
<refsect2 id="g-signal-newv" role="function">
681
<title>g_signal_newv ()</title>
682
<indexterm zone="g-signal-newv"><primary sortas="signal_newv">g_signal_newv</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_newv (const <link linkend="gchar">gchar</link> *signal_name,
683
<link linkend="GType">GType</link> itype,
684
<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
685
<link linkend="GClosure">GClosure</link> *class_closure,
686
<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
687
<link linkend="gpointer">gpointer</link> accu_data,
688
<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
689
<link linkend="GType">GType</link> return_type,
690
<link linkend="guint">guint</link> n_params,
691
<link linkend="GType">GType</link> *param_types);</programlisting>
693
Creates a new signal. (This is usually done in the class initializer.)
696
See <link linkend="g-signal-new"><function>g_signal_new()</function></link> for details on allowed signal names.</para>
698
</para><variablelist role="params">
699
<varlistentry><term><parameter>signal_name</parameter> :</term>
700
<listitem><simpara> the name for the signal
701
</simpara></listitem></varlistentry>
702
<varlistentry><term><parameter>itype</parameter> :</term>
703
<listitem><simpara> the type this signal pertains to. It will also pertain to
704
types which are derived from this type
705
</simpara></listitem></varlistentry>
706
<varlistentry><term><parameter>signal_flags</parameter> :</term>
707
<listitem><simpara> a combination of <link linkend="GSignalFlags"><type>GSignalFlags</type></link> specifying detail of when
708
the default handler is to be invoked. You should at least specify
709
<link linkend="G-SIGNAL-RUN-FIRST--CAPS"><literal>G_SIGNAL_RUN_FIRST</literal></link> or <link linkend="G-SIGNAL-RUN-LAST--CAPS"><literal>G_SIGNAL_RUN_LAST</literal></link>
710
</simpara></listitem></varlistentry>
711
<varlistentry><term><parameter>class_closure</parameter> :</term>
712
<listitem><simpara> The closure to invoke on signal emission; may be <link linkend="NULL--CAPS"><literal>NULL</literal></link>
713
</simpara></listitem></varlistentry>
714
<varlistentry><term><parameter>accumulator</parameter> :</term>
715
<listitem><simpara> the accumulator for this signal; may be <link linkend="NULL--CAPS"><literal>NULL</literal></link>
716
</simpara></listitem></varlistentry>
717
<varlistentry><term><parameter>accu_data</parameter> :</term>
718
<listitem><simpara> user data for the <parameter>accumulator</parameter>
719
</simpara></listitem></varlistentry>
720
<varlistentry><term><parameter>c_marshaller</parameter> :</term>
721
<listitem><simpara> the function to translate arrays of parameter values to
722
signal emissions into C language callback invocations
723
</simpara></listitem></varlistentry>
724
<varlistentry><term><parameter>return_type</parameter> :</term>
725
<listitem><simpara> the type of return value, or <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link> for a signal
726
without a return value
727
</simpara></listitem></varlistentry>
728
<varlistentry><term><parameter>n_params</parameter> :</term>
729
<listitem><simpara> the length of <parameter>param_types</parameter>
730
</simpara></listitem></varlistentry>
731
<varlistentry><term><parameter>param_types</parameter> :</term>
732
<listitem><simpara> an array of types, one for each parameter
733
</simpara></listitem></varlistentry>
734
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the signal id
735
</simpara></listitem></varlistentry>
736
</variablelist></refsect2>
737
<refsect2 id="g-signal-new-valist" role="function">
738
<title>g_signal_new_valist ()</title>
739
<indexterm zone="g-signal-new-valist"><primary sortas="signal_new_valist">g_signal_new_valist</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_new_valist (const <link linkend="gchar">gchar</link> *signal_name,
740
<link linkend="GType">GType</link> itype,
741
<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
742
<link linkend="GClosure">GClosure</link> *class_closure,
743
<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
744
<link linkend="gpointer">gpointer</link> accu_data,
745
<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
746
<link linkend="GType">GType</link> return_type,
747
<link linkend="guint">guint</link> n_params,
748
<link linkend="va-list">va_list</link> args);</programlisting>
750
Creates a new signal. (This is usually done in the class initializer.)
753
See <link linkend="g-signal-new"><function>g_signal_new()</function></link> for details on allowed signal names.</para>
755
</para><variablelist role="params">
756
<varlistentry><term><parameter>signal_name</parameter> :</term>
757
<listitem><simpara> the name for the signal
758
</simpara></listitem></varlistentry>
759
<varlistentry><term><parameter>itype</parameter> :</term>
760
<listitem><simpara> the type this signal pertains to. It will also pertain to
761
types which are derived from this type.
762
</simpara></listitem></varlistentry>
763
<varlistentry><term><parameter>signal_flags</parameter> :</term>
764
<listitem><simpara> a combination of <link linkend="GSignalFlags"><type>GSignalFlags</type></link> specifying detail of when
765
the default handler is to be invoked. You should at least specify
766
<link linkend="G-SIGNAL-RUN-FIRST--CAPS"><literal>G_SIGNAL_RUN_FIRST</literal></link> or <link linkend="G-SIGNAL-RUN-LAST--CAPS"><literal>G_SIGNAL_RUN_LAST</literal></link>.
767
</simpara></listitem></varlistentry>
768
<varlistentry><term><parameter>class_closure</parameter> :</term>
769
<listitem><simpara> The closure to invoke on signal emission; may be <link linkend="NULL--CAPS"><literal>NULL</literal></link>.
770
</simpara></listitem></varlistentry>
771
<varlistentry><term><parameter>accumulator</parameter> :</term>
772
<listitem><simpara> the accumulator for this signal; may be <link linkend="NULL--CAPS"><literal>NULL</literal></link>.
773
</simpara></listitem></varlistentry>
774
<varlistentry><term><parameter>accu_data</parameter> :</term>
775
<listitem><simpara> user data for the <parameter>accumulator</parameter>.
776
</simpara></listitem></varlistentry>
777
<varlistentry><term><parameter>c_marshaller</parameter> :</term>
778
<listitem><simpara> the function to translate arrays of parameter values to
779
signal emissions into C language callback invocations.
780
</simpara></listitem></varlistentry>
781
<varlistentry><term><parameter>return_type</parameter> :</term>
782
<listitem><simpara> the type of return value, or <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link> for a signal
783
without a return value.
784
</simpara></listitem></varlistentry>
785
<varlistentry><term><parameter>n_params</parameter> :</term>
786
<listitem><simpara> the number of parameter types in <parameter>args</parameter>.
787
</simpara></listitem></varlistentry>
788
<varlistentry><term><parameter>args</parameter> :</term>
789
<listitem><simpara> va_list of <link linkend="GType"><type>GType</type></link>, one for each parameter.
790
</simpara></listitem></varlistentry>
791
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the signal id
792
</simpara></listitem></varlistentry>
793
</variablelist></refsect2>
794
<refsect2 id="g-signal-query" role="function">
795
<title>g_signal_query ()</title>
796
<indexterm zone="g-signal-query"><primary sortas="signal_query">g_signal_query</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_query (<link linkend="guint">guint</link> signal_id,
797
<link linkend="GSignalQuery">GSignalQuery</link> *query);</programlisting>
799
Queries the signal system for in-depth information about a
800
specific signal. This function will fill in a user-provided
801
structure to hold signal-specific information. If an invalid
802
signal id is passed in, the <parameter>signal_id</parameter> member of the <link linkend="GSignalQuery"><type>GSignalQuery</type></link>
803
is 0. All members filled into the <link linkend="GSignalQuery"><type>GSignalQuery</type></link> structure should
804
be considered constant and have to be left untouched.</para>
806
</para><variablelist role="params">
807
<varlistentry><term><parameter>signal_id</parameter> :</term>
808
<listitem><simpara> The signal id of the signal to query information for.
809
</simpara></listitem></varlistentry>
810
<varlistentry><term><parameter>query</parameter> :</term>
811
<listitem><simpara> A user provided structure that is filled in with constant
813
</simpara></listitem></varlistentry>
814
</variablelist></refsect2>
815
<refsect2 id="g-signal-lookup" role="function">
816
<title>g_signal_lookup ()</title>
817
<indexterm zone="g-signal-lookup"><primary sortas="signal_lookup">g_signal_lookup</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_lookup (const <link linkend="gchar">gchar</link> *name,
818
<link linkend="GType">GType</link> itype);</programlisting>
820
Given the name of the signal and the type of object it connects to, gets
821
the signal's identifying integer. Emitting the signal by number is
822
somewhat faster than using the name each time.
825
Also tries the ancestors of the given type.
828
See <link linkend="g-signal-new"><function>g_signal_new()</function></link> for details on allowed signal names.</para>
830
</para><variablelist role="params">
831
<varlistentry><term><parameter>name</parameter> :</term>
832
<listitem><simpara> the signal's name.
833
</simpara></listitem></varlistentry>
834
<varlistentry><term><parameter>itype</parameter> :</term>
835
<listitem><simpara> the type that the signal operates on.
836
</simpara></listitem></varlistentry>
837
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the signal's identifying number, or 0 if no signal was found.
838
</simpara></listitem></varlistentry>
839
</variablelist></refsect2>
840
<refsect2 id="g-signal-name" role="function">
841
<title>g_signal_name ()</title>
842
<indexterm zone="g-signal-name"><primary sortas="signal_name">g_signal_name</primary></indexterm><programlisting>const <link linkend="gchar">gchar</link>* g_signal_name (<link linkend="guint">guint</link> signal_id);</programlisting>
844
Given the signal's identifier, finds its name.
847
Two different signals may have the same name, if they have differing types.</para>
849
</para><variablelist role="params">
850
<varlistentry><term><parameter>signal_id</parameter> :</term>
851
<listitem><simpara> the signal's identifying number.
852
</simpara></listitem></varlistentry>
853
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the signal name, or <link linkend="NULL--CAPS"><literal>NULL</literal></link> if the signal number was invalid.
854
</simpara></listitem></varlistentry>
855
</variablelist></refsect2>
856
<refsect2 id="g-signal-list-ids" role="function">
857
<title>g_signal_list_ids ()</title>
858
<indexterm zone="g-signal-list-ids"><primary sortas="signal_list_ids">g_signal_list_ids</primary></indexterm><programlisting><link linkend="guint">guint</link>* g_signal_list_ids (<link linkend="GType">GType</link> itype,
859
<link linkend="guint">guint</link> *n_ids);</programlisting>
861
Lists the signals by id that a certain instance or interface type
862
created. Further information about the signals can be acquired through
863
<link linkend="g-signal-query"><function>g_signal_query()</function></link>.</para>
865
</para><variablelist role="params">
866
<varlistentry><term><parameter>itype</parameter> :</term>
867
<listitem><simpara> Instance or interface type.
868
</simpara></listitem></varlistentry>
869
<varlistentry><term><parameter>n_ids</parameter> :</term>
870
<listitem><simpara> Location to store the number of signal ids for <parameter>itype</parameter>.
871
</simpara></listitem></varlistentry>
872
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> Newly allocated array of signal IDs.
873
</simpara></listitem></varlistentry>
874
</variablelist></refsect2>
875
<refsect2 id="g-signal-emit" role="function">
876
<title>g_signal_emit ()</title>
877
<indexterm zone="g-signal-emit"><primary sortas="signal_emit">g_signal_emit</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_emit (<link linkend="gpointer">gpointer</link> instance,
878
<link linkend="guint">guint</link> signal_id,
879
<link linkend="GQuark">GQuark</link> detail,
880
...);</programlisting>
885
Note that <link linkend="g-signal-emit"><function>g_signal_emit()</function></link> resets the return value to the default
886
if no handlers are connected, in contrast to <link linkend="g-signal-emitv"><function>g_signal_emitv()</function></link>.</para>
888
</para><variablelist role="params">
889
<varlistentry><term><parameter>instance</parameter> :</term>
890
<listitem><simpara> the instance the signal is being emitted on.
891
</simpara></listitem></varlistentry>
892
<varlistentry><term><parameter>signal_id</parameter> :</term>
893
<listitem><simpara> the signal id
894
</simpara></listitem></varlistentry>
895
<varlistentry><term><parameter>detail</parameter> :</term>
896
<listitem><simpara> the detail
897
</simpara></listitem></varlistentry>
898
<varlistentry><term><parameter>...</parameter> :</term>
899
<listitem><simpara> parameters to be passed to the signal, followed by a
900
location for the return value. If the return type of the signal
901
is <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link>, the return value location can be omitted.
902
</simpara></listitem></varlistentry>
903
</variablelist></refsect2>
904
<refsect2 id="g-signal-emit-by-name" role="function">
905
<title>g_signal_emit_by_name ()</title>
906
<indexterm zone="g-signal-emit-by-name"><primary sortas="signal_emit_by_name">g_signal_emit_by_name</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_emit_by_name (<link linkend="gpointer">gpointer</link> instance,
907
const <link linkend="gchar">gchar</link> *detailed_signal,
908
...);</programlisting>
913
Note that <link linkend="g-signal-emit-by-name"><function>g_signal_emit_by_name()</function></link> resets the return value to the default
914
if no handlers are connected, in contrast to <link linkend="g-signal-emitv"><function>g_signal_emitv()</function></link>.</para>
916
</para><variablelist role="params">
917
<varlistentry><term><parameter>instance</parameter> :</term>
918
<listitem><simpara> the instance the signal is being emitted on.
919
</simpara></listitem></varlistentry>
920
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
921
<listitem><simpara> a string of the form "signal-name::detail".
922
</simpara></listitem></varlistentry>
923
<varlistentry><term><parameter>...</parameter> :</term>
924
<listitem><simpara> parameters to be passed to the signal, followed by a
925
location for the return value. If the return type of the signal
926
is <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link>, the return value location can be omitted.
927
</simpara></listitem></varlistentry>
928
</variablelist></refsect2>
929
<refsect2 id="g-signal-emitv" role="function">
930
<title>g_signal_emitv ()</title>
931
<indexterm zone="g-signal-emitv"><primary sortas="signal_emitv">g_signal_emitv</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_emitv (const <link linkend="GValue">GValue</link> *instance_and_params,
932
<link linkend="guint">guint</link> signal_id,
933
<link linkend="GQuark">GQuark</link> detail,
934
<link linkend="GValue">GValue</link> *return_value);</programlisting>
939
Note that <link linkend="g-signal-emitv"><function>g_signal_emitv()</function></link> doesn't change <parameter>return_value</parameter> if no handlers are
940
connected, in contrast to <link linkend="g-signal-emit"><function>g_signal_emit()</function></link> and <link linkend="g-signal-emit-valist"><function>g_signal_emit_valist()</function></link>.</para>
942
</para><variablelist role="params">
943
<varlistentry><term><parameter>instance_and_params</parameter> :</term>
944
<listitem><simpara> argument list for the signal emission. The first
945
element in the array is a <link linkend="GValue"><type>GValue</type></link> for the instance the signal is
946
being emitted on. The rest are any arguments to be passed to the
948
</simpara></listitem></varlistentry>
949
<varlistentry><term><parameter>signal_id</parameter> :</term>
950
<listitem><simpara> the signal id
951
</simpara></listitem></varlistentry>
952
<varlistentry><term><parameter>detail</parameter> :</term>
953
<listitem><simpara> the detail
954
</simpara></listitem></varlistentry>
955
<varlistentry><term><parameter>return_value</parameter> :</term>
956
<listitem><simpara> Location to store the return value of the signal emission.
957
</simpara></listitem></varlistentry>
958
</variablelist></refsect2>
959
<refsect2 id="g-signal-emit-valist" role="function">
960
<title>g_signal_emit_valist ()</title>
961
<indexterm zone="g-signal-emit-valist"><primary sortas="signal_emit_valist">g_signal_emit_valist</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_emit_valist (<link linkend="gpointer">gpointer</link> instance,
962
<link linkend="guint">guint</link> signal_id,
963
<link linkend="GQuark">GQuark</link> detail,
964
<link linkend="va-list">va_list</link> var_args);</programlisting>
969
Note that <link linkend="g-signal-emit-valist"><function>g_signal_emit_valist()</function></link> resets the return value to the default
970
if no handlers are connected, in contrast to <link linkend="g-signal-emitv"><function>g_signal_emitv()</function></link>.</para>
972
</para><variablelist role="params">
973
<varlistentry><term><parameter>instance</parameter> :</term>
974
<listitem><simpara> the instance the signal is being emitted on.
975
</simpara></listitem></varlistentry>
976
<varlistentry><term><parameter>signal_id</parameter> :</term>
977
<listitem><simpara> the signal id
978
</simpara></listitem></varlistentry>
979
<varlistentry><term><parameter>detail</parameter> :</term>
980
<listitem><simpara> the detail
981
</simpara></listitem></varlistentry>
982
<varlistentry><term><parameter>var_args</parameter> :</term>
983
<listitem><simpara> a list of parameters to be passed to the signal, followed by a
984
location for the return value. If the return type of the signal
985
is <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link>, the return value location can be omitted.
986
</simpara></listitem></varlistentry>
987
</variablelist></refsect2>
988
<refsect2 id="g-signal-connect" role="macro">
989
<title>g_signal_connect()</title>
990
<indexterm zone="g-signal-connect"><primary sortas="signal_connect">g_signal_connect</primary></indexterm><programlisting>#define g_signal_connect(instance, detailed_signal, c_handler, data)</programlisting>
992
Connects a <link linkend="GCallback"><type>GCallback</type></link> function to a signal for a particular object.
995
The handler will be called before the default handler of the signal.</para>
997
</para><variablelist role="params">
998
<varlistentry><term><parameter>instance</parameter> :</term>
999
<listitem><simpara> the instance to connect to.
1000
</simpara></listitem></varlistentry>
1001
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1002
<listitem><simpara> a string of the form "signal-name::detail".
1003
</simpara></listitem></varlistentry>
1004
<varlistentry><term><parameter>c_handler</parameter> :</term>
1005
<listitem><simpara> the <link linkend="GCallback"><type>GCallback</type></link> to connect.
1006
</simpara></listitem></varlistentry>
1007
<varlistentry><term><parameter>data</parameter> :</term>
1008
<listitem><simpara> data to pass to <parameter>c_handler</parameter> calls.
1009
</simpara></listitem></varlistentry>
1010
</variablelist></refsect2>
1011
<refsect2 id="g-signal-connect-after" role="macro">
1012
<title>g_signal_connect_after()</title>
1013
<indexterm zone="g-signal-connect-after"><primary sortas="signal_connect_after">g_signal_connect_after</primary></indexterm><programlisting>#define g_signal_connect_after(instance, detailed_signal, c_handler, data)</programlisting>
1015
Connects a <link linkend="GCallback"><type>GCallback</type></link> function to a signal for a particular object.
1018
The handler will be called after the default handler of the signal.</para>
1020
</para><variablelist role="params">
1021
<varlistentry><term><parameter>instance</parameter> :</term>
1022
<listitem><simpara> the instance to connect to.
1023
</simpara></listitem></varlistentry>
1024
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1025
<listitem><simpara> a string of the form "signal-name::detail".
1026
</simpara></listitem></varlistentry>
1027
<varlistentry><term><parameter>c_handler</parameter> :</term>
1028
<listitem><simpara> the <link linkend="GCallback"><type>GCallback</type></link> to connect.
1029
</simpara></listitem></varlistentry>
1030
<varlistentry><term><parameter>data</parameter> :</term>
1031
<listitem><simpara> data to pass to <parameter>c_handler</parameter> calls.
1032
</simpara></listitem></varlistentry>
1033
</variablelist></refsect2>
1034
<refsect2 id="g-signal-connect-swapped" role="macro">
1035
<title>g_signal_connect_swapped()</title>
1036
<indexterm zone="g-signal-connect-swapped"><primary sortas="signal_connect_swapped">g_signal_connect_swapped</primary></indexterm><programlisting>#define g_signal_connect_swapped(instance, detailed_signal, c_handler, data)</programlisting>
1038
Connects a <link linkend="GCallback"><type>GCallback</type></link> function to a signal for a particular object.
1041
The instance on which the signal is emitted and <parameter>data</parameter> will be swapped when
1042
calling the handler.</para>
1044
</para><variablelist role="params">
1045
<varlistentry><term><parameter>instance</parameter> :</term>
1046
<listitem><simpara> the instance to connect to.
1047
</simpara></listitem></varlistentry>
1048
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1049
<listitem><simpara> a string of the form "signal-name::detail".
1050
</simpara></listitem></varlistentry>
1051
<varlistentry><term><parameter>c_handler</parameter> :</term>
1052
<listitem><simpara> the <link linkend="GCallback"><type>GCallback</type></link> to connect.
1053
</simpara></listitem></varlistentry>
1054
<varlistentry><term><parameter>data</parameter> :</term>
1055
<listitem><simpara> data to pass to <parameter>c_handler</parameter> calls.
1056
</simpara></listitem></varlistentry>
1057
</variablelist></refsect2>
1058
<refsect2 id="g-signal-connect-object" role="function">
1059
<title>g_signal_connect_object ()</title>
1060
<indexterm zone="g-signal-connect-object"><primary sortas="signal_connect_object">g_signal_connect_object</primary></indexterm><programlisting><link linkend="gulong">gulong</link> g_signal_connect_object (<link linkend="gpointer">gpointer</link> instance,
1061
const <link linkend="gchar">gchar</link> *detailed_signal,
1062
<link linkend="GCallback">GCallback</link> c_handler,
1063
<link linkend="gpointer">gpointer</link> gobject,
1064
<link linkend="GConnectFlags">GConnectFlags</link> connect_flags);</programlisting>
1066
This is similar to <link linkend="g-signal-connect-data"><function>g_signal_connect_data()</function></link>, but uses a closure which
1067
ensures that the <parameter>gobject</parameter> stays alive during the call to <parameter>c_handler</parameter>
1068
by temporarily adding a reference count to <parameter>gobject</parameter>.
1071
Note that there is a bug in GObject that makes this function
1072
much less useful than it might seem otherwise. Once <parameter>gobject</parameter> is
1073
disposed, the callback will no longer be called, but, the signal
1074
handler is <emphasis>not</emphasis> currently disconnected. If the
1075
<parameter>instance</parameter> is itself being freed at the same time than this doesn't
1076
matter, since the signal will automatically be removed, but
1077
if <parameter>instance</parameter> persists, then the signal handler will leak. You
1078
should not remove the signal yourself because in a future versions of
1079
GObject, the handler <emphasis>will</emphasis> automatically
1083
It's possible to work around this problem in a way that will
1084
continue to work with future versions of GObject by checking
1085
that the signal handler is still connected before disconnected it:
1086
<informalexample><programlisting>
1087
if (g_signal_handler_is_connected (instance, id))
1088
g_signal_handler_disconnect (instance, id);
1089
</programlisting></informalexample></para>
1091
</para><variablelist role="params">
1092
<varlistentry><term><parameter>instance</parameter> :</term>
1093
<listitem><simpara> the instance to connect to.
1094
</simpara></listitem></varlistentry>
1095
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1096
<listitem><simpara> a string of the form "signal-name::detail".
1097
</simpara></listitem></varlistentry>
1098
<varlistentry><term><parameter>c_handler</parameter> :</term>
1099
<listitem><simpara> the <link linkend="GCallback"><type>GCallback</type></link> to connect.
1100
</simpara></listitem></varlistentry>
1101
<varlistentry><term><parameter>gobject</parameter> :</term>
1102
<listitem><simpara> the object to pass as data to <parameter>c_handler</parameter>.
1103
</simpara></listitem></varlistentry>
1104
<varlistentry><term><parameter>connect_flags</parameter> :</term>
1105
<listitem><simpara> a combination of <link linkend="GConnnectFlags"><type>GConnnectFlags</type></link>.
1106
</simpara></listitem></varlistentry>
1107
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the handler id.
1108
</simpara></listitem></varlistentry>
1109
</variablelist></refsect2>
1110
<refsect2 id="GConnectFlags" role="enum">
1111
<title>enum GConnectFlags</title>
1112
<indexterm zone="GConnectFlags"><primary sortas="ConnectFlags">GConnectFlags</primary></indexterm><programlisting>typedef enum
1114
G_CONNECT_AFTER = 1 << 0,
1115
G_CONNECT_SWAPPED = 1 << 1
1119
The connection flags are used to specify the behaviour of a signal's
1122
</para><variablelist role="enum">
1123
<varlistentry id="G-CONNECT-AFTER--CAPS" role="constant">
1124
<term><literal>G_CONNECT_AFTER</literal></term>
1125
<listitem><simpara> whether the handler should be called before or after the
1126
default handler of the signal.
1127
</simpara></listitem>
1129
<varlistentry id="G-CONNECT-SWAPPED--CAPS" role="constant">
1130
<term><literal>G_CONNECT_SWAPPED</literal></term>
1131
<listitem><simpara> whether the instance and data should be swapped when
1132
calling the handler.
1133
</simpara></listitem>
1135
</variablelist></refsect2>
1136
<refsect2 id="g-signal-connect-data" role="function">
1137
<title>g_signal_connect_data ()</title>
1138
<indexterm zone="g-signal-connect-data"><primary sortas="signal_connect_data">g_signal_connect_data</primary></indexterm><programlisting><link linkend="gulong">gulong</link> g_signal_connect_data (<link linkend="gpointer">gpointer</link> instance,
1139
const <link linkend="gchar">gchar</link> *detailed_signal,
1140
<link linkend="GCallback">GCallback</link> c_handler,
1141
<link linkend="gpointer">gpointer</link> data,
1142
<link linkend="GClosureNotify">GClosureNotify</link> destroy_data,
1143
<link linkend="GConnectFlags">GConnectFlags</link> connect_flags);</programlisting>
1145
Connects a <link linkend="GCallback"><type>GCallback</type></link> function to a signal for a particular object. Similar
1146
to <link linkend="g-signal-connect"><function>g_signal_connect()</function></link>, but allows to provide a <link linkend="GClosureNotify"><type>GClosureNotify</type></link> for the data
1147
which will be called when the signal handler is disconnected and no longer
1148
used. Specify <parameter>connect_flags</parameter> if you need <literal>...<link linkend="after"><function>_after()</function></link></literal> or
1149
<literal>...<link linkend="swapped"><function>_swapped()</function></link></literal> variants of this function.</para>
1151
</para><variablelist role="params">
1152
<varlistentry><term><parameter>instance</parameter> :</term>
1153
<listitem><simpara> the instance to connect to.
1154
</simpara></listitem></varlistentry>
1155
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1156
<listitem><simpara> a string of the form "signal-name::detail".
1157
</simpara></listitem></varlistentry>
1158
<varlistentry><term><parameter>c_handler</parameter> :</term>
1159
<listitem><simpara> the <link linkend="GCallback"><type>GCallback</type></link> to connect.
1160
</simpara></listitem></varlistentry>
1161
<varlistentry><term><parameter>data</parameter> :</term>
1162
<listitem><simpara> data to pass to <parameter>c_handler</parameter> calls.
1163
</simpara></listitem></varlistentry>
1164
<varlistentry><term><parameter>destroy_data</parameter> :</term>
1165
<listitem><simpara> a <link linkend="GClosureNotify"><type>GClosureNotify</type></link> for <parameter>data</parameter>.
1166
</simpara></listitem></varlistentry>
1167
<varlistentry><term><parameter>connect_flags</parameter> :</term>
1168
<listitem><simpara> a combination of <link linkend="GConnectFlags"><type>GConnectFlags</type></link>.
1169
</simpara></listitem></varlistentry>
1170
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the handler id
1171
</simpara></listitem></varlistentry>
1172
</variablelist></refsect2>
1173
<refsect2 id="g-signal-connect-closure" role="function">
1174
<title>g_signal_connect_closure ()</title>
1175
<indexterm zone="g-signal-connect-closure"><primary sortas="signal_connect_closure">g_signal_connect_closure</primary></indexterm><programlisting><link linkend="gulong">gulong</link> g_signal_connect_closure (<link linkend="gpointer">gpointer</link> instance,
1176
const <link linkend="gchar">gchar</link> *detailed_signal,
1177
<link linkend="GClosure">GClosure</link> *closure,
1178
<link linkend="gboolean">gboolean</link> after);</programlisting>
1180
Connects a closure to a signal for a particular object.</para>
1182
</para><variablelist role="params">
1183
<varlistentry><term><parameter>instance</parameter> :</term>
1184
<listitem><simpara> the instance to connect to.
1185
</simpara></listitem></varlistentry>
1186
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1187
<listitem><simpara> a string of the form "signal-name::detail".
1188
</simpara></listitem></varlistentry>
1189
<varlistentry><term><parameter>closure</parameter> :</term>
1190
<listitem><simpara> the closure to connect.
1191
</simpara></listitem></varlistentry>
1192
<varlistentry><term><parameter>after</parameter> :</term>
1193
<listitem><simpara> whether the handler should be called before or after the
1194
default handler of the signal.
1195
</simpara></listitem></varlistentry>
1196
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the handler id
1197
</simpara></listitem></varlistentry>
1198
</variablelist></refsect2>
1199
<refsect2 id="g-signal-connect-closure-by-id" role="function">
1200
<title>g_signal_connect_closure_by_id ()</title>
1201
<indexterm zone="g-signal-connect-closure-by-id"><primary sortas="signal_connect_closure_by_id">g_signal_connect_closure_by_id</primary></indexterm><programlisting><link linkend="gulong">gulong</link> g_signal_connect_closure_by_id (<link linkend="gpointer">gpointer</link> instance,
1202
<link linkend="guint">guint</link> signal_id,
1203
<link linkend="GQuark">GQuark</link> detail,
1204
<link linkend="GClosure">GClosure</link> *closure,
1205
<link linkend="gboolean">gboolean</link> after);</programlisting>
1207
Connects a closure to a signal for a particular object.</para>
1209
</para><variablelist role="params">
1210
<varlistentry><term><parameter>instance</parameter> :</term>
1211
<listitem><simpara> the instance to connect to.
1212
</simpara></listitem></varlistentry>
1213
<varlistentry><term><parameter>signal_id</parameter> :</term>
1214
<listitem><simpara> the id of the signal.
1215
</simpara></listitem></varlistentry>
1216
<varlistentry><term><parameter>detail</parameter> :</term>
1217
<listitem><simpara> the detail.
1218
</simpara></listitem></varlistentry>
1219
<varlistentry><term><parameter>closure</parameter> :</term>
1220
<listitem><simpara> the closure to connect.
1221
</simpara></listitem></varlistentry>
1222
<varlistentry><term><parameter>after</parameter> :</term>
1223
<listitem><simpara> whether the handler should be called before or after the
1224
default handler of the signal.
1225
</simpara></listitem></varlistentry>
1226
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the handler id
1227
</simpara></listitem></varlistentry>
1228
</variablelist></refsect2>
1229
<refsect2 id="g-signal-handler-block" role="function">
1230
<title>g_signal_handler_block ()</title>
1231
<indexterm zone="g-signal-handler-block"><primary sortas="signal_handler_block">g_signal_handler_block</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_handler_block (<link linkend="gpointer">gpointer</link> instance,
1232
<link linkend="gulong">gulong</link> handler_id);</programlisting>
1234
Blocks a handler of an instance so it will not be called during any
1235
signal emissions unless it is unblocked again. Thus "blocking" a
1236
signal handler means to temporarily deactive it, a signal handler
1237
has to be unblocked exactly the same amount of times it has been
1238
blocked before to become active again.
1241
The <parameter>handler_id</parameter> has to be a valid signal handler id, connected to a
1242
signal of <parameter>instance</parameter>.</para>
1244
</para><variablelist role="params">
1245
<varlistentry><term><parameter>instance</parameter> :</term>
1246
<listitem><simpara> The instance to block the signal handler of.
1247
</simpara></listitem></varlistentry>
1248
<varlistentry><term><parameter>handler_id</parameter> :</term>
1249
<listitem><simpara> Handler id of the handler to be blocked.
1250
</simpara></listitem></varlistentry>
1251
</variablelist></refsect2>
1252
<refsect2 id="g-signal-handler-unblock" role="function">
1253
<title>g_signal_handler_unblock ()</title>
1254
<indexterm zone="g-signal-handler-unblock"><primary sortas="signal_handler_unblock">g_signal_handler_unblock</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_handler_unblock (<link linkend="gpointer">gpointer</link> instance,
1255
<link linkend="gulong">gulong</link> handler_id);</programlisting>
1257
Undoes the effect of a previous <link linkend="g-signal-handler-block"><function>g_signal_handler_block()</function></link> call. A
1258
blocked handler is skipped during signal emissions and will not be
1259
invoked, unblocking it (for exactly the amount of times it has been
1260
blocked before) reverts its "blocked" state, so the handler will be
1261
recognized by the signal system and is called upon future or
1262
currently ongoing signal emissions (since the order in which
1263
handlers are called during signal emissions is deterministic,
1264
whether the unblocked handler in question is called as part of a
1265
currently ongoing emission depends on how far that emission has
1269
The <parameter>handler_id</parameter> has to be a valid id of a signal handler that is
1270
connected to a signal of <parameter>instance</parameter> and is currently blocked.</para>
1272
</para><variablelist role="params">
1273
<varlistentry><term><parameter>instance</parameter> :</term>
1274
<listitem><simpara> The instance to unblock the signal handler of.
1275
</simpara></listitem></varlistentry>
1276
<varlistentry><term><parameter>handler_id</parameter> :</term>
1277
<listitem><simpara> Handler id of the handler to be unblocked.
1278
</simpara></listitem></varlistentry>
1279
</variablelist></refsect2>
1280
<refsect2 id="g-signal-handler-disconnect" role="function">
1281
<title>g_signal_handler_disconnect ()</title>
1282
<indexterm zone="g-signal-handler-disconnect"><primary sortas="signal_handler_disconnect">g_signal_handler_disconnect</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_handler_disconnect (<link linkend="gpointer">gpointer</link> instance,
1283
<link linkend="gulong">gulong</link> handler_id);</programlisting>
1285
Disconnects a handler from an instance so it will not be called during
1286
any future or currently ongoing emissions of the signal it has been
1287
connected to. The <parameter>handler_id</parameter> becomes invalid and may be reused.
1290
The <parameter>handler_id</parameter> has to be a valid signal handler id, connected to a
1291
signal of <parameter>instance</parameter>.</para>
1293
</para><variablelist role="params">
1294
<varlistentry><term><parameter>instance</parameter> :</term>
1295
<listitem><simpara> The instance to remove the signal handler from.
1296
</simpara></listitem></varlistentry>
1297
<varlistentry><term><parameter>handler_id</parameter> :</term>
1298
<listitem><simpara> Handler id of the handler to be disconnected.
1299
</simpara></listitem></varlistentry>
1300
</variablelist></refsect2>
1301
<refsect2 id="g-signal-handler-find" role="function">
1302
<title>g_signal_handler_find ()</title>
1303
<indexterm zone="g-signal-handler-find"><primary sortas="signal_handler_find">g_signal_handler_find</primary></indexterm><programlisting><link linkend="gulong">gulong</link> g_signal_handler_find (<link linkend="gpointer">gpointer</link> instance,
1304
<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
1305
<link linkend="guint">guint</link> signal_id,
1306
<link linkend="GQuark">GQuark</link> detail,
1307
<link linkend="GClosure">GClosure</link> *closure,
1308
<link linkend="gpointer">gpointer</link> func,
1309
<link linkend="gpointer">gpointer</link> data);</programlisting>
1311
Finds the first signal handler that matches certain selection criteria.
1312
The criteria mask is passed as an OR-ed combination of <link linkend="GSignalMatchType"><type>GSignalMatchType</type></link>
1313
flags, and the criteria values are passed as arguments.
1314
The match <parameter>mask</parameter> has to be non-0 for successful matches.
1315
If no handler was found, 0 is returned.</para>
1317
</para><variablelist role="params">
1318
<varlistentry><term><parameter>instance</parameter> :</term>
1319
<listitem><simpara> The instance owning the signal handler to be found.
1320
</simpara></listitem></varlistentry>
1321
<varlistentry><term><parameter>mask</parameter> :</term>
1322
<listitem><simpara> Mask indicating which of <parameter>signal_id</parameter>, <parameter>detail</parameter>, <parameter>closure</parameter>, <parameter>func</parameter>
1323
and/or <parameter>data</parameter> the handler has to match.
1324
</simpara></listitem></varlistentry>
1325
<varlistentry><term><parameter>signal_id</parameter> :</term>
1326
<listitem><simpara> Signal the handler has to be connected to.
1327
</simpara></listitem></varlistentry>
1328
<varlistentry><term><parameter>detail</parameter> :</term>
1329
<listitem><simpara> Signal detail the handler has to be connected to.
1330
</simpara></listitem></varlistentry>
1331
<varlistentry><term><parameter>closure</parameter> :</term>
1332
<listitem><simpara> The closure the handler will invoke.
1333
</simpara></listitem></varlistentry>
1334
<varlistentry><term><parameter>func</parameter> :</term>
1335
<listitem><simpara> The C closure callback of the handler (useless for non-C closures).
1336
</simpara></listitem></varlistentry>
1337
<varlistentry><term><parameter>data</parameter> :</term>
1338
<listitem><simpara> The closure data of the handler's closure.
1339
</simpara></listitem></varlistentry>
1340
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> A valid non-0 signal handler id for a successful match.
1341
</simpara></listitem></varlistentry>
1342
</variablelist></refsect2>
1343
<refsect2 id="g-signal-handlers-block-matched" role="function">
1344
<title>g_signal_handlers_block_matched ()</title>
1345
<indexterm zone="g-signal-handlers-block-matched"><primary sortas="signal_handlers_block_matched">g_signal_handlers_block_matched</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_handlers_block_matched (<link linkend="gpointer">gpointer</link> instance,
1346
<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
1347
<link linkend="guint">guint</link> signal_id,
1348
<link linkend="GQuark">GQuark</link> detail,
1349
<link linkend="GClosure">GClosure</link> *closure,
1350
<link linkend="gpointer">gpointer</link> func,
1351
<link linkend="gpointer">gpointer</link> data);</programlisting>
1353
Blocks all handlers on an instance that match a certain selection criteria.
1354
The criteria mask is passed as an OR-ed combination of <link linkend="GSignalMatchType"><type>GSignalMatchType</type></link>
1355
flags, and the criteria values are passed as arguments.
1356
Passing at least one of the <link linkend="G-SIGNAL-MATCH-CLOSURE--CAPS"><literal>G_SIGNAL_MATCH_CLOSURE</literal></link>, <link linkend="G-SIGNAL-MATCH-FUNC--CAPS"><literal>G_SIGNAL_MATCH_FUNC</literal></link>
1357
or <link linkend="G-SIGNAL-MATCH-DATA--CAPS"><literal>G_SIGNAL_MATCH_DATA</literal></link> match flags is required for successful matches.
1358
If no handlers were found, 0 is returned, the number of blocked handlers
1361
</para><variablelist role="params">
1362
<varlistentry><term><parameter>instance</parameter> :</term>
1363
<listitem><simpara> The instance to block handlers from.
1364
</simpara></listitem></varlistentry>
1365
<varlistentry><term><parameter>mask</parameter> :</term>
1366
<listitem><simpara> Mask indicating which of <parameter>signal_id</parameter>, <parameter>detail</parameter>, <parameter>closure</parameter>, <parameter>func</parameter>
1367
and/or <parameter>data</parameter> the handlers have to match.
1368
</simpara></listitem></varlistentry>
1369
<varlistentry><term><parameter>signal_id</parameter> :</term>
1370
<listitem><simpara> Signal the handlers have to be connected to.
1371
</simpara></listitem></varlistentry>
1372
<varlistentry><term><parameter>detail</parameter> :</term>
1373
<listitem><simpara> Signal detail the handlers have to be connected to.
1374
</simpara></listitem></varlistentry>
1375
<varlistentry><term><parameter>closure</parameter> :</term>
1376
<listitem><simpara> The closure the handlers will invoke.
1377
</simpara></listitem></varlistentry>
1378
<varlistentry><term><parameter>func</parameter> :</term>
1379
<listitem><simpara> The C closure callback of the handlers (useless for non-C closures).
1380
</simpara></listitem></varlistentry>
1381
<varlistentry><term><parameter>data</parameter> :</term>
1382
<listitem><simpara> The closure data of the handlers' closures.
1383
</simpara></listitem></varlistentry>
1384
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> The number of handlers that matched.
1385
</simpara></listitem></varlistentry>
1386
</variablelist></refsect2>
1387
<refsect2 id="g-signal-handlers-unblock-matched" role="function">
1388
<title>g_signal_handlers_unblock_matched ()</title>
1389
<indexterm zone="g-signal-handlers-unblock-matched"><primary sortas="signal_handlers_unblock_matched">g_signal_handlers_unblock_matched</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_handlers_unblock_matched (<link linkend="gpointer">gpointer</link> instance,
1390
<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
1391
<link linkend="guint">guint</link> signal_id,
1392
<link linkend="GQuark">GQuark</link> detail,
1393
<link linkend="GClosure">GClosure</link> *closure,
1394
<link linkend="gpointer">gpointer</link> func,
1395
<link linkend="gpointer">gpointer</link> data);</programlisting>
1397
Unblocks all handlers on an instance that match a certain selection
1398
criteria. The criteria mask is passed as an OR-ed combination of
1399
<link linkend="GSignalMatchType"><type>GSignalMatchType</type></link> flags, and the criteria values are passed as arguments.
1400
Passing at least one of the <link linkend="G-SIGNAL-MATCH-CLOSURE--CAPS"><literal>G_SIGNAL_MATCH_CLOSURE</literal></link>, <link linkend="G-SIGNAL-MATCH-FUNC--CAPS"><literal>G_SIGNAL_MATCH_FUNC</literal></link>
1401
or <link linkend="G-SIGNAL-MATCH-DATA--CAPS"><literal>G_SIGNAL_MATCH_DATA</literal></link> match flags is required for successful matches.
1402
If no handlers were found, 0 is returned, the number of unblocked handlers
1403
otherwise. The match criteria should not apply to any handlers that are
1404
not currently blocked.</para>
1406
</para><variablelist role="params">
1407
<varlistentry><term><parameter>instance</parameter> :</term>
1408
<listitem><simpara> The instance to unblock handlers from.
1409
</simpara></listitem></varlistentry>
1410
<varlistentry><term><parameter>mask</parameter> :</term>
1411
<listitem><simpara> Mask indicating which of <parameter>signal_id</parameter>, <parameter>detail</parameter>, <parameter>closure</parameter>, <parameter>func</parameter>
1412
and/or <parameter>data</parameter> the handlers have to match.
1413
</simpara></listitem></varlistentry>
1414
<varlistentry><term><parameter>signal_id</parameter> :</term>
1415
<listitem><simpara> Signal the handlers have to be connected to.
1416
</simpara></listitem></varlistentry>
1417
<varlistentry><term><parameter>detail</parameter> :</term>
1418
<listitem><simpara> Signal detail the handlers have to be connected to.
1419
</simpara></listitem></varlistentry>
1420
<varlistentry><term><parameter>closure</parameter> :</term>
1421
<listitem><simpara> The closure the handlers will invoke.
1422
</simpara></listitem></varlistentry>
1423
<varlistentry><term><parameter>func</parameter> :</term>
1424
<listitem><simpara> The C closure callback of the handlers (useless for non-C closures).
1425
</simpara></listitem></varlistentry>
1426
<varlistentry><term><parameter>data</parameter> :</term>
1427
<listitem><simpara> The closure data of the handlers' closures.
1428
</simpara></listitem></varlistentry>
1429
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> The number of handlers that matched.
1430
</simpara></listitem></varlistentry>
1431
</variablelist></refsect2>
1432
<refsect2 id="g-signal-handlers-disconnect-matched" role="function">
1433
<title>g_signal_handlers_disconnect_matched ()</title>
1434
<indexterm zone="g-signal-handlers-disconnect-matched"><primary sortas="signal_handlers_disconnect_matched">g_signal_handlers_disconnect_matched</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_handlers_disconnect_matched
1435
(<link linkend="gpointer">gpointer</link> instance,
1436
<link linkend="GSignalMatchType">GSignalMatchType</link> mask,
1437
<link linkend="guint">guint</link> signal_id,
1438
<link linkend="GQuark">GQuark</link> detail,
1439
<link linkend="GClosure">GClosure</link> *closure,
1440
<link linkend="gpointer">gpointer</link> func,
1441
<link linkend="gpointer">gpointer</link> data);</programlisting>
1443
Disconnects all handlers on an instance that match a certain
1444
selection criteria. The criteria mask is passed as an OR-ed
1445
combination of <link linkend="GSignalMatchType"><type>GSignalMatchType</type></link> flags, and the criteria values are
1446
passed as arguments. Passing at least one of the
1447
<link linkend="G-SIGNAL-MATCH-CLOSURE--CAPS"><literal>G_SIGNAL_MATCH_CLOSURE</literal></link>, <link linkend="G-SIGNAL-MATCH-FUNC--CAPS"><literal>G_SIGNAL_MATCH_FUNC</literal></link> or
1448
<link linkend="G-SIGNAL-MATCH-DATA--CAPS"><literal>G_SIGNAL_MATCH_DATA</literal></link> match flags is required for successful
1449
matches. If no handlers were found, 0 is returned, the number of
1450
disconnected handlers otherwise.</para>
1452
</para><variablelist role="params">
1453
<varlistentry><term><parameter>instance</parameter> :</term>
1454
<listitem><simpara> The instance to remove handlers from.
1455
</simpara></listitem></varlistentry>
1456
<varlistentry><term><parameter>mask</parameter> :</term>
1457
<listitem><simpara> Mask indicating which of <parameter>signal_id</parameter>, <parameter>detail</parameter>, <parameter>closure</parameter>, <parameter>func</parameter>
1458
and/or <parameter>data</parameter> the handlers have to match.
1459
</simpara></listitem></varlistentry>
1460
<varlistentry><term><parameter>signal_id</parameter> :</term>
1461
<listitem><simpara> Signal the handlers have to be connected to.
1462
</simpara></listitem></varlistentry>
1463
<varlistentry><term><parameter>detail</parameter> :</term>
1464
<listitem><simpara> Signal detail the handlers have to be connected to.
1465
</simpara></listitem></varlistentry>
1466
<varlistentry><term><parameter>closure</parameter> :</term>
1467
<listitem><simpara> The closure the handlers will invoke.
1468
</simpara></listitem></varlistentry>
1469
<varlistentry><term><parameter>func</parameter> :</term>
1470
<listitem><simpara> The C closure callback of the handlers (useless for non-C closures).
1471
</simpara></listitem></varlistentry>
1472
<varlistentry><term><parameter>data</parameter> :</term>
1473
<listitem><simpara> The closure data of the handlers' closures.
1474
</simpara></listitem></varlistentry>
1475
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> The number of handlers that matched.
1476
</simpara></listitem></varlistentry>
1477
</variablelist></refsect2>
1478
<refsect2 id="g-signal-handler-is-connected" role="function">
1479
<title>g_signal_handler_is_connected ()</title>
1480
<indexterm zone="g-signal-handler-is-connected"><primary sortas="signal_handler_is_connected">g_signal_handler_is_connected</primary></indexterm><programlisting><link linkend="gboolean">gboolean</link> g_signal_handler_is_connected (<link linkend="gpointer">gpointer</link> instance,
1481
<link linkend="gulong">gulong</link> handler_id);</programlisting>
1483
Returns whether <parameter>handler_id</parameter> is the id of a handler connected to <parameter>instance</parameter>.</para>
1485
</para><variablelist role="params">
1486
<varlistentry><term><parameter>instance</parameter> :</term>
1487
<listitem><simpara> The instance where a signal handler is sought.
1488
</simpara></listitem></varlistentry>
1489
<varlistentry><term><parameter>handler_id</parameter> :</term>
1490
<listitem><simpara> the handler id.
1491
</simpara></listitem></varlistentry>
1492
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> whether <parameter>handler_id</parameter> identifies a handler connected to <parameter>instance</parameter>.
1493
</simpara></listitem></varlistentry>
1494
</variablelist></refsect2>
1495
<refsect2 id="g-signal-handlers-block-by-func" role="macro">
1496
<title>g_signal_handlers_block_by_func()</title>
1497
<indexterm zone="g-signal-handlers-block-by-func"><primary sortas="signal_handlers_block_by_func">g_signal_handlers_block_by_func</primary></indexterm><programlisting>#define g_signal_handlers_block_by_func(instance, func, data)</programlisting>
1499
Blocks all handlers on an instance that match <parameter>func</parameter> and <parameter>data</parameter>.</para>
1501
</para><variablelist role="params">
1502
<varlistentry><term><parameter>instance</parameter> :</term>
1503
<listitem><simpara> The instance to block handlers from.
1504
</simpara></listitem></varlistentry>
1505
<varlistentry><term><parameter>func</parameter> :</term>
1506
<listitem><simpara> The C closure callback of the handlers (useless for non-C closures).
1507
</simpara></listitem></varlistentry>
1508
<varlistentry><term><parameter>data</parameter> :</term>
1509
<listitem><simpara> The closure data of the handlers' closures.
1510
</simpara></listitem></varlistentry>
1511
</variablelist></refsect2>
1512
<refsect2 id="g-signal-handlers-unblock-by-func" role="macro">
1513
<title>g_signal_handlers_unblock_by_func()</title>
1514
<indexterm zone="g-signal-handlers-unblock-by-func"><primary sortas="signal_handlers_unblock_by_func">g_signal_handlers_unblock_by_func</primary></indexterm><programlisting>#define g_signal_handlers_unblock_by_func(instance, func, data)</programlisting>
1516
Unblocks all handlers on an instance that match <parameter>func</parameter> and <parameter>data</parameter>.</para>
1518
</para><variablelist role="params">
1519
<varlistentry><term><parameter>instance</parameter> :</term>
1520
<listitem><simpara> The instance to unblock handlers from.
1521
</simpara></listitem></varlistentry>
1522
<varlistentry><term><parameter>func</parameter> :</term>
1523
<listitem><simpara> The C closure callback of the handlers (useless for non-C closures).
1524
</simpara></listitem></varlistentry>
1525
<varlistentry><term><parameter>data</parameter> :</term>
1526
<listitem><simpara> The closure data of the handlers' closures.
1527
</simpara></listitem></varlistentry>
1528
</variablelist></refsect2>
1529
<refsect2 id="g-signal-handlers-disconnect-by-func" role="macro">
1530
<title>g_signal_handlers_disconnect_by_func()</title>
1531
<indexterm zone="g-signal-handlers-disconnect-by-func"><primary sortas="signal_handlers_disconnect_by_func">g_signal_handlers_disconnect_by_func</primary></indexterm><programlisting>#define g_signal_handlers_disconnect_by_func(instance, func, data)</programlisting>
1533
Disconnects all handlers on an instance that match <parameter>func</parameter> and <parameter>data</parameter>.</para>
1535
</para><variablelist role="params">
1536
<varlistentry><term><parameter>instance</parameter> :</term>
1537
<listitem><simpara> The instance to remove handlers from.
1538
</simpara></listitem></varlistentry>
1539
<varlistentry><term><parameter>func</parameter> :</term>
1540
<listitem><simpara> The C closure callback of the handlers (useless for non-C closures).
1541
</simpara></listitem></varlistentry>
1542
<varlistentry><term><parameter>data</parameter> :</term>
1543
<listitem><simpara> The closure data of the handlers' closures.
1544
</simpara></listitem></varlistentry>
1545
</variablelist></refsect2>
1546
<refsect2 id="g-signal-has-handler-pending" role="function">
1547
<title>g_signal_has_handler_pending ()</title>
1548
<indexterm zone="g-signal-has-handler-pending"><primary sortas="signal_has_handler_pending">g_signal_has_handler_pending</primary></indexterm><programlisting><link linkend="gboolean">gboolean</link> g_signal_has_handler_pending (<link linkend="gpointer">gpointer</link> instance,
1549
<link linkend="guint">guint</link> signal_id,
1550
<link linkend="GQuark">GQuark</link> detail,
1551
<link linkend="gboolean">gboolean</link> may_be_blocked);</programlisting>
1553
Returns whether there are any handlers connected to <parameter>instance</parameter> for the
1554
given signal id and detail.
1557
One example of when you might use this is when the arguments to the
1558
signal are difficult to compute. A class implementor may opt to not
1559
emit the signal if no one is attached anyway, thus saving the cost
1560
of building the arguments.</para>
1562
</para><variablelist role="params">
1563
<varlistentry><term><parameter>instance</parameter> :</term>
1564
<listitem><simpara> the object whose signal handlers are sought.
1565
</simpara></listitem></varlistentry>
1566
<varlistentry><term><parameter>signal_id</parameter> :</term>
1567
<listitem><simpara> the signal id.
1568
</simpara></listitem></varlistentry>
1569
<varlistentry><term><parameter>detail</parameter> :</term>
1570
<listitem><simpara> the detail.
1571
</simpara></listitem></varlistentry>
1572
<varlistentry><term><parameter>may_be_blocked</parameter> :</term>
1573
<listitem><simpara> whether blocked handlers should count as match.
1574
</simpara></listitem></varlistentry>
1575
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> <link linkend="TRUE--CAPS"><literal>TRUE</literal></link> if a handler is connected to the signal, <link linkend="FALSE--CAPS"><literal>FALSE</literal></link>
1577
</simpara></listitem></varlistentry>
1578
</variablelist></refsect2>
1579
<refsect2 id="g-signal-stop-emission" role="function">
1580
<title>g_signal_stop_emission ()</title>
1581
<indexterm zone="g-signal-stop-emission"><primary sortas="signal_stop_emission">g_signal_stop_emission</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_stop_emission (<link linkend="gpointer">gpointer</link> instance,
1582
<link linkend="guint">guint</link> signal_id,
1583
<link linkend="GQuark">GQuark</link> detail);</programlisting>
1585
Stops a signal's current emission.
1588
This will prevent the default method from running, if the signal was
1589
<link linkend="G-SIGNAL-RUN-LAST--CAPS"><literal>G_SIGNAL_RUN_LAST</literal></link> and you connected normally (i.e. without the "after"
1593
Prints a warning if used on a signal which isn't being emitted.</para>
1595
</para><variablelist role="params">
1596
<varlistentry><term><parameter>instance</parameter> :</term>
1597
<listitem><simpara> the object whose signal handlers you wish to stop.
1598
</simpara></listitem></varlistentry>
1599
<varlistentry><term><parameter>signal_id</parameter> :</term>
1600
<listitem><simpara> the signal identifier, as returned by <link linkend="g-signal-lookup"><function>g_signal_lookup()</function></link>.
1601
</simpara></listitem></varlistentry>
1602
<varlistentry><term><parameter>detail</parameter> :</term>
1603
<listitem><simpara> the detail which the signal was emitted with.
1604
</simpara></listitem></varlistentry>
1605
</variablelist></refsect2>
1606
<refsect2 id="g-signal-stop-emission-by-name" role="function">
1607
<title>g_signal_stop_emission_by_name ()</title>
1608
<indexterm zone="g-signal-stop-emission-by-name"><primary sortas="signal_stop_emission_by_name">g_signal_stop_emission_by_name</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_stop_emission_by_name (<link linkend="gpointer">gpointer</link> instance,
1609
const <link linkend="gchar">gchar</link> *detailed_signal);</programlisting>
1611
Stops a signal's current emission.
1614
This is just like <link linkend="g-signal-stop-emission"><function>g_signal_stop_emission()</function></link> except it will look up the
1615
signal id for you.</para>
1617
</para><variablelist role="params">
1618
<varlistentry><term><parameter>instance</parameter> :</term>
1619
<listitem><simpara> the object whose signal handlers you wish to stop.
1620
</simpara></listitem></varlistentry>
1621
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1622
<listitem><simpara> a string of the form "signal-name::detail".
1623
</simpara></listitem></varlistentry>
1624
</variablelist></refsect2>
1625
<refsect2 id="g-signal-override-class-closure" role="function">
1626
<title>g_signal_override_class_closure ()</title>
1627
<indexterm zone="g-signal-override-class-closure"><primary sortas="signal_override_class_closure">g_signal_override_class_closure</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_override_class_closure (<link linkend="guint">guint</link> signal_id,
1628
<link linkend="GType">GType</link> instance_type,
1629
<link linkend="GClosure">GClosure</link> *class_closure);</programlisting>
1631
Overrides the class closure (i.e. the default handler) for the given signal
1632
for emissions on instances of <parameter>instance_type</parameter>. <parameter>instance_type</parameter> must be derived
1633
from the type to which the signal belongs.
1636
See <link linkend="g-signal-chain-from-overridden"><function>g_signal_chain_from_overridden()</function></link> and
1637
<link linkend="g-signal-chain-from-overridden-handler"><function>g_signal_chain_from_overridden_handler()</function></link> for how to chain up to the
1638
parent class closure from inside the overridden one.</para>
1640
</para><variablelist role="params">
1641
<varlistentry><term><parameter>signal_id</parameter> :</term>
1642
<listitem><simpara> the signal id
1643
</simpara></listitem></varlistentry>
1644
<varlistentry><term><parameter>instance_type</parameter> :</term>
1645
<listitem><simpara> the instance type on which to override the class closure
1647
</simpara></listitem></varlistentry>
1648
<varlistentry><term><parameter>class_closure</parameter> :</term>
1649
<listitem><simpara> the closure.
1650
</simpara></listitem></varlistentry>
1651
</variablelist></refsect2>
1652
<refsect2 id="g-signal-chain-from-overridden" role="function">
1653
<title>g_signal_chain_from_overridden ()</title>
1654
<indexterm zone="g-signal-chain-from-overridden"><primary sortas="signal_chain_from_overridden">g_signal_chain_from_overridden</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_chain_from_overridden (const <link linkend="GValue">GValue</link> *instance_and_params,
1655
<link linkend="GValue">GValue</link> *return_value);</programlisting>
1657
Calls the original class closure of a signal. This function should only
1658
be called from an overridden class closure; see
1659
<link linkend="g-signal-override-class-closure"><function>g_signal_override_class_closure()</function></link> and
1660
<link linkend="g-signal-override-class-handler"><function>g_signal_override_class_handler()</function></link>.</para>
1662
</para><variablelist role="params">
1663
<varlistentry><term><parameter>instance_and_params</parameter> :</term>
1664
<listitem><simpara> the argument list of the signal emission. The first
1665
element in the array is a <link linkend="GValue"><type>GValue</type></link> for the instance the signal is being
1666
emitted on. The rest are any arguments to be passed to the signal.
1667
</simpara></listitem></varlistentry>
1668
<varlistentry><term><parameter>return_value</parameter> :</term>
1669
<listitem><simpara> Location for the return value.
1670
</simpara></listitem></varlistentry>
1671
</variablelist></refsect2>
1672
<refsect2 id="g-signal-new-class-handler" role="function" condition="since:2.18">
1673
<title>g_signal_new_class_handler ()</title>
1674
<indexterm zone="g-signal-new-class-handler" role="2.18"><primary sortas="signal_new_class_handler">g_signal_new_class_handler</primary></indexterm><programlisting><link linkend="guint">guint</link> g_signal_new_class_handler (const <link linkend="gchar">gchar</link> *signal_name,
1675
<link linkend="GType">GType</link> itype,
1676
<link linkend="GSignalFlags">GSignalFlags</link> signal_flags,
1677
<link linkend="GCallback">GCallback</link> class_handler,
1678
<link linkend="GSignalAccumulator">GSignalAccumulator</link> accumulator,
1679
<link linkend="gpointer">gpointer</link> accu_data,
1680
<link linkend="GSignalCMarshaller">GSignalCMarshaller</link> c_marshaller,
1681
<link linkend="GType">GType</link> return_type,
1682
<link linkend="guint">guint</link> n_params,
1683
...);</programlisting>
1685
Creates a new signal. (This is usually done in the class initializer.)
1688
This is a variant of <link linkend="g-signal-new"><function>g_signal_new()</function></link> that takes a C callback instead
1689
off a class offset for the signal's class handler. This function
1690
doesn't need a function pointer exposed in the class structure of
1691
an object definition, instead the function pointer is passed
1692
directly and can be overriden by derived classes with
1693
<link linkend="g-signal-override-class-closure"><function>g_signal_override_class_closure()</function></link> or
1694
<link linkend="g-signal-override-class-handler"><function>g_signal_override_class_handler()</function></link>and chained to with
1695
<link linkend="g-signal-chain-from-overridden"><function>g_signal_chain_from_overridden()</function></link> or
1696
<link linkend="g-signal-chain-from-overridden-handler"><function>g_signal_chain_from_overridden_handler()</function></link>.
1699
See <link linkend="g-signal-new"><function>g_signal_new()</function></link> for information about signal names.</para>
1701
</para><variablelist role="params">
1702
<varlistentry><term><parameter>signal_name</parameter> :</term>
1703
<listitem><simpara> the name for the signal
1704
</simpara></listitem></varlistentry>
1705
<varlistentry><term><parameter>itype</parameter> :</term>
1706
<listitem><simpara> the type this signal pertains to. It will also pertain to
1707
types which are derived from this type.
1708
</simpara></listitem></varlistentry>
1709
<varlistentry><term><parameter>signal_flags</parameter> :</term>
1710
<listitem><simpara> a combination of <link linkend="GSignalFlags"><type>GSignalFlags</type></link> specifying detail of when
1711
the default handler is to be invoked. You should at least specify
1712
<link linkend="G-SIGNAL-RUN-FIRST--CAPS"><literal>G_SIGNAL_RUN_FIRST</literal></link> or <link linkend="G-SIGNAL-RUN-LAST--CAPS"><literal>G_SIGNAL_RUN_LAST</literal></link>.
1713
</simpara></listitem></varlistentry>
1714
<varlistentry><term><parameter>class_handler</parameter> :</term>
1715
<listitem><simpara> a <link linkend="GCallback"><type>GCallback</type></link> which acts as class implementation of
1716
this signal. Used to invoke a class method generically. Pass <link linkend="NULL--CAPS"><literal>NULL</literal></link> to
1717
not associate a class method with this signal.
1718
</simpara></listitem></varlistentry>
1719
<varlistentry><term><parameter>accumulator</parameter> :</term>
1720
<listitem><simpara> the accumulator for this signal; may be <link linkend="NULL--CAPS"><literal>NULL</literal></link>.
1721
</simpara></listitem></varlistentry>
1722
<varlistentry><term><parameter>accu_data</parameter> :</term>
1723
<listitem><simpara> user data for the <parameter>accumulator</parameter>.
1724
</simpara></listitem></varlistentry>
1725
<varlistentry><term><parameter>c_marshaller</parameter> :</term>
1726
<listitem><simpara> the function to translate arrays of parameter values to
1727
signal emissions into C language callback invocations.
1728
</simpara></listitem></varlistentry>
1729
<varlistentry><term><parameter>return_type</parameter> :</term>
1730
<listitem><simpara> the type of return value, or <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link> for a signal
1731
without a return value.
1732
</simpara></listitem></varlistentry>
1733
<varlistentry><term><parameter>n_params</parameter> :</term>
1734
<listitem><simpara> the number of parameter types to follow.
1735
</simpara></listitem></varlistentry>
1736
<varlistentry><term><parameter>...</parameter> :</term>
1737
<listitem><simpara> a list of types, one for each parameter.
1738
</simpara></listitem></varlistentry>
1739
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the signal id
1741
</simpara></listitem></varlistentry>
1742
</variablelist><para role="since">Since 2.18</para></refsect2>
1743
<refsect2 id="g-signal-override-class-handler" role="function" condition="since:2.18">
1744
<title>g_signal_override_class_handler ()</title>
1745
<indexterm zone="g-signal-override-class-handler" role="2.18"><primary sortas="signal_override_class_handler">g_signal_override_class_handler</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_override_class_handler (const <link linkend="gchar">gchar</link> *signal_name,
1746
<link linkend="GType">GType</link> instance_type,
1747
<link linkend="GCallback">GCallback</link> class_handler);</programlisting>
1749
Overrides the class closure (i.e. the default handler) for the
1750
given signal for emissions on instances of <parameter>instance_type</parameter> with
1751
callabck <parameter>class_handler</parameter>. <parameter>instance_type</parameter> must be derived from the
1752
type to which the signal belongs.
1755
See <link linkend="g-signal-chain-from-overridden"><function>g_signal_chain_from_overridden()</function></link> and
1756
<link linkend="g-signal-chain-from-overridden-handler"><function>g_signal_chain_from_overridden_handler()</function></link> for how to chain up to the
1757
parent class closure from inside the overridden one.</para>
1759
</para><variablelist role="params">
1760
<varlistentry><term><parameter>signal_name</parameter> :</term>
1761
<listitem><simpara> the name for the signal
1762
</simpara></listitem></varlistentry>
1763
<varlistentry><term><parameter>instance_type</parameter> :</term>
1764
<listitem><simpara> the instance type on which to override the class handler
1766
</simpara></listitem></varlistentry>
1767
<varlistentry><term><parameter>class_handler</parameter> :</term>
1768
<listitem><simpara> the handler.
1769
</simpara></listitem></varlistentry>
1770
</variablelist><para role="since">Since 2.18</para></refsect2>
1771
<refsect2 id="g-signal-chain-from-overridden-handler" role="function" condition="since:2.18">
1772
<title>g_signal_chain_from_overridden_handler ()</title>
1773
<indexterm zone="g-signal-chain-from-overridden-handler" role="2.18"><primary sortas="signal_chain_from_overridden_handler">g_signal_chain_from_overridden_handler</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_chain_from_overridden_handler
1774
(<link linkend="gpointer">gpointer</link> instance,
1775
...);</programlisting>
1777
Calls the original class closure of a signal. This function should
1778
only be called from an overridden class closure; see
1779
<link linkend="g-signal-override-class-closure"><function>g_signal_override_class_closure()</function></link> and
1780
<link linkend="g-signal-override-class-handler"><function>g_signal_override_class_handler()</function></link>.</para>
1782
</para><variablelist role="params">
1783
<varlistentry><term><parameter>instance</parameter> :</term>
1784
<listitem><simpara> the instance the signal is being emitted on.
1785
</simpara></listitem></varlistentry>
1786
<varlistentry><term><parameter>...</parameter> :</term>
1787
<listitem><simpara> parameters to be passed to the parent class closure, followed by a
1788
location for the return value. If the return type of the signal
1789
is <link linkend="G-TYPE-NONE--CAPS"><type>G_TYPE_NONE</type></link>, the return value location can be omitted.
1790
</simpara></listitem></varlistentry>
1791
</variablelist><para role="since">Since 2.18</para></refsect2>
1792
<refsect2 id="g-signal-add-emission-hook" role="function">
1793
<title>g_signal_add_emission_hook ()</title>
1794
<indexterm zone="g-signal-add-emission-hook"><primary sortas="signal_add_emission_hook">g_signal_add_emission_hook</primary></indexterm><programlisting><link linkend="gulong">gulong</link> g_signal_add_emission_hook (<link linkend="guint">guint</link> signal_id,
1795
<link linkend="GQuark">GQuark</link> detail,
1796
<link linkend="GSignalEmissionHook">GSignalEmissionHook</link> hook_func,
1797
<link linkend="gpointer">gpointer</link> hook_data,
1798
<link linkend="GDestroyNotify">GDestroyNotify</link> data_destroy);</programlisting>
1800
Adds an emission hook for a signal, which will get called for any emission
1801
of that signal, independent of the instance. This is possible only
1802
for signals which don't have <link linkend="G-SIGNAL-NO-HOOKS--CAPS"><type>G_SIGNAL_NO_HOOKS</type></link> flag set.</para>
1804
</para><variablelist role="params">
1805
<varlistentry><term><parameter>signal_id</parameter> :</term>
1806
<listitem><simpara> the signal identifier, as returned by <link linkend="g-signal-lookup"><function>g_signal_lookup()</function></link>.
1807
</simpara></listitem></varlistentry>
1808
<varlistentry><term><parameter>detail</parameter> :</term>
1809
<listitem><simpara> the detail on which to call the hook.
1810
</simpara></listitem></varlistentry>
1811
<varlistentry><term><parameter>hook_func</parameter> :</term>
1812
<listitem><simpara> a <link linkend="GSignalEmissionHook"><type>GSignalEmissionHook</type></link> function.
1813
</simpara></listitem></varlistentry>
1814
<varlistentry><term><parameter>hook_data</parameter> :</term>
1815
<listitem><simpara> user data for <parameter>hook_func</parameter>.
1816
</simpara></listitem></varlistentry>
1817
<varlistentry><term><parameter>data_destroy</parameter> :</term>
1818
<listitem><simpara> a <link linkend="GDestroyNotify"><type>GDestroyNotify</type></link> for <parameter>hook_data</parameter>.
1819
</simpara></listitem></varlistentry>
1820
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the hook id, for later use with <link linkend="g-signal-remove-emission-hook"><function>g_signal_remove_emission_hook()</function></link>.
1821
</simpara></listitem></varlistentry>
1822
</variablelist></refsect2>
1823
<refsect2 id="g-signal-remove-emission-hook" role="function">
1824
<title>g_signal_remove_emission_hook ()</title>
1825
<indexterm zone="g-signal-remove-emission-hook"><primary sortas="signal_remove_emission_hook">g_signal_remove_emission_hook</primary></indexterm><programlisting><link linkend="void">void</link> g_signal_remove_emission_hook (<link linkend="guint">guint</link> signal_id,
1826
<link linkend="gulong">gulong</link> hook_id);</programlisting>
1828
Deletes an emission hook.</para>
1830
</para><variablelist role="params">
1831
<varlistentry><term><parameter>signal_id</parameter> :</term>
1832
<listitem><simpara> the id of the signal
1833
</simpara></listitem></varlistentry>
1834
<varlistentry><term><parameter>hook_id</parameter> :</term>
1835
<listitem><simpara> the id of the emission hook, as returned by
1836
<link linkend="g-signal-add-emission-hook"><function>g_signal_add_emission_hook()</function></link>
1837
</simpara></listitem></varlistentry>
1838
</variablelist></refsect2>
1839
<refsect2 id="g-signal-parse-name" role="function">
1840
<title>g_signal_parse_name ()</title>
1841
<indexterm zone="g-signal-parse-name"><primary sortas="signal_parse_name">g_signal_parse_name</primary></indexterm><programlisting><link linkend="gboolean">gboolean</link> g_signal_parse_name (const <link linkend="gchar">gchar</link> *detailed_signal,
1842
<link linkend="GType">GType</link> itype,
1843
<link linkend="guint">guint</link> *signal_id_p,
1844
<link linkend="GQuark">GQuark</link> *detail_p,
1845
<link linkend="gboolean">gboolean</link> force_detail_quark);</programlisting>
1847
Internal function to parse a signal name into its <parameter>signal_id</parameter>
1848
and <parameter>detail</parameter> quark.</para>
1850
</para><variablelist role="params">
1851
<varlistentry><term><parameter>detailed_signal</parameter> :</term>
1852
<listitem><simpara> a string of the form "signal-name::detail".
1853
</simpara></listitem></varlistentry>
1854
<varlistentry><term><parameter>itype</parameter> :</term>
1855
<listitem><simpara> The interface/instance type that introduced "signal-name".
1856
</simpara></listitem></varlistentry>
1857
<varlistentry><term><parameter>signal_id_p</parameter> :</term>
1858
<listitem><simpara> Location to store the signal id.
1859
</simpara></listitem></varlistentry>
1860
<varlistentry><term><parameter>detail_p</parameter> :</term>
1861
<listitem><simpara> Location to store the detail quark.
1862
</simpara></listitem></varlistentry>
1863
<varlistentry><term><parameter>force_detail_quark</parameter> :</term>
1864
<listitem><simpara> <link linkend="TRUE--CAPS"><literal>TRUE</literal></link> forces creation of a <link linkend="GQuark"><type>GQuark</type></link> for the detail.
1865
</simpara></listitem></varlistentry>
1866
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> Whether the signal name could successfully be parsed and <parameter>signal_id_p</parameter> and <parameter>detail_p</parameter> contain valid return values.
1867
</simpara></listitem></varlistentry>
1868
</variablelist></refsect2>
1869
<refsect2 id="g-signal-get-invocation-hint" role="function">
1870
<title>g_signal_get_invocation_hint ()</title>
1871
<indexterm zone="g-signal-get-invocation-hint"><primary sortas="signal_get_invocation_hint">g_signal_get_invocation_hint</primary></indexterm><programlisting><link linkend="GSignalInvocationHint">GSignalInvocationHint</link>* g_signal_get_invocation_hint (<link linkend="gpointer">gpointer</link> instance);</programlisting>
1873
Returns the invocation hint of the innermost signal emission of instance.</para>
1875
</para><variablelist role="params">
1876
<varlistentry><term><parameter>instance</parameter> :</term>
1877
<listitem><simpara> the instance to query
1878
</simpara></listitem></varlistentry>
1879
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> the invocation hint of the innermost signal emission.
1880
</simpara></listitem></varlistentry>
1881
</variablelist></refsect2>
1882
<refsect2 id="g-signal-type-cclosure-new" role="function">
1883
<title>g_signal_type_cclosure_new ()</title>
1884
<indexterm zone="g-signal-type-cclosure-new"><primary sortas="signal_type_cclosure_new">g_signal_type_cclosure_new</primary></indexterm><programlisting><link linkend="GClosure">GClosure</link>* g_signal_type_cclosure_new (<link linkend="GType">GType</link> itype,
1885
<link linkend="guint">guint</link> struct_offset);</programlisting>
1887
Creates a new closure which invokes the function found at the offset
1888
<parameter>struct_offset</parameter> in the class structure of the interface or classed type
1889
identified by <parameter>itype</parameter>.</para>
1891
</para><variablelist role="params">
1892
<varlistentry><term><parameter>itype</parameter> :</term>
1893
<listitem><simpara> the <link linkend="GType"><type>GType</type></link> identifier of an interface or classed type
1894
</simpara></listitem></varlistentry>
1895
<varlistentry><term><parameter>struct_offset</parameter> :</term>
1896
<listitem><simpara> the offset of the member function of <parameter>itype</parameter>'s class
1897
structure which is to be invoked by the new closure
1898
</simpara></listitem></varlistentry>
1899
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> a new <link linkend="GCClosure"><type>GCClosure</type></link>
1900
</simpara></listitem></varlistentry>
1901
</variablelist></refsect2>
1902
<refsect2 id="g-signal-accumulator-true-handled" role="function" condition="since:2.4">
1903
<title>g_signal_accumulator_true_handled ()</title>
1904
<indexterm zone="g-signal-accumulator-true-handled" role="2.4"><primary sortas="signal_accumulator_true_handled">g_signal_accumulator_true_handled</primary></indexterm><programlisting><link linkend="gboolean">gboolean</link> g_signal_accumulator_true_handled (<link linkend="GSignalInvocationHint">GSignalInvocationHint</link> *ihint,
1905
<link linkend="GValue">GValue</link> *return_accu,
1906
const <link linkend="GValue">GValue</link> *handler_return,
1907
<link linkend="gpointer">gpointer</link> dummy);</programlisting>
1909
A predefined <link linkend="GSignalAccumulator"><type>GSignalAccumulator</type></link> for signals that return a
1910
boolean values. The behavior that this accumulator gives is
1911
that a return of <link linkend="TRUE--CAPS"><literal>TRUE</literal></link> stops the signal emission: no further
1912
callbacks will be invoked, while a return of <link linkend="FALSE--CAPS"><literal>FALSE</literal></link> allows
1913
the emission to coninue. The idea here is that a <link linkend="TRUE--CAPS"><literal>TRUE</literal></link> return
1914
indicates that the callback <emphasis>handled</emphasis> the signal,
1915
and no further handling is needed.</para>
1917
</para><variablelist role="params">
1918
<varlistentry><term><parameter>ihint</parameter> :</term>
1919
<listitem><simpara> standard <link linkend="GSignalAccumulator"><type>GSignalAccumulator</type></link> parameter
1920
</simpara></listitem></varlistentry>
1921
<varlistentry><term><parameter>return_accu</parameter> :</term>
1922
<listitem><simpara> standard <link linkend="GSignalAccumulator"><type>GSignalAccumulator</type></link> parameter
1923
</simpara></listitem></varlistentry>
1924
<varlistentry><term><parameter>handler_return</parameter> :</term>
1925
<listitem><simpara> standard <link linkend="GSignalAccumulator"><type>GSignalAccumulator</type></link> parameter
1926
</simpara></listitem></varlistentry>
1927
<varlistentry><term><parameter>dummy</parameter> :</term>
1928
<listitem><simpara> standard <link linkend="GSignalAccumulator"><type>GSignalAccumulator</type></link> parameter
1929
</simpara></listitem></varlistentry>
1930
<varlistentry><term><emphasis>Returns</emphasis> :</term><listitem><simpara> standard <link linkend="GSignalAccumulator"><type>GSignalAccumulator</type></link> result
1931
</simpara></listitem></varlistentry>
1932
</variablelist><para role="since">Since 2.4</para></refsect2>
added
removed
docs/reference/gobject/xml/signals.xml
